THE  LIBRARY 

OF 

THE  UNIVERSITY 
OF  CALIFORNIA 

GEOLOGY  LIBRARY 
IN  MEMORY  OF 

PROFESSOR 

GEORGE  D.  LOUDERBACK 
1874-1957        EAtTH 

•open 


HANDBOOK 


FOR 


FIELD  GEOLOGISTS 


BT 

C.   W.   HAYES,   PH.D. 

Formerly  Chief  Geologist,  United  States  Geological  Survey 


SECOND    EDITION,    THOROUGHLY   REVISED 
THIRD   THOUSAND 


NEW  YORK 

JOHN  WILEY  &   SONS,   INC. 

LONDON:  CHAPMAN  &   HALL,  LIMITED 

1916 


Copyright,  1909 
By  C.   W.    HAYES 


THE  SCIENTIFIC   PRESS 

ROBERT  DHUMMOND   AND  COMPANY 

BROOKLYN,    N.    Y, 


#£•45 

H 


Kouif 


EAKTH 

PREFACE  scrENct 

LIBRARY 


MEMBERS  of  the  -TJ.  S.  Geological  Survey  have  for  some  time 
felt  the  need  of  a  convenient  and  concise  description  of  geologic 
field  methods.  An  attempt  to  meet  this  need  was  made  by  the 
publication,  in  1908,  of  a  Handbook  for  Field  Geologists  in  the 
United  States  Geological  Survey.  This  work  was  intended  for 
distribution  only  to  members  of  the  Survey,  and  only  a  small 
edition  was  issued.  The  requests  for  copies  of  the  Handbook, 
which  have  come  in  from  members  of  State  Surveys,  teachers, 
mining  geologists,  and  others,  indicate  a  genuine  need  for  some- 
thing of  the  kind  among  geologists  generally.  The  present  work 
is  written  in  response  to  this  evident  demand.  The  Survey  Hand- 
book has  been  used  in  the  preparation  of  this  work,  omitting  those 
instructions  which  apply  only  to  members  of  the  Government 
Survey,  and  enlarging  upon  certain  features  which  will  be  of 
service  to  students  preparing  for  work  in  field  geology. 

In  geologic  field  work,  as  in  most  other  things,  there  are  cer- 
tain methods  of  procedure  which  have  been  found  by  experience 
better  than  others,  and  poor  or  wrong  methods  result  in  loss  of 
efficiency.  While  many  of  the  suggestions  given  may  appear 
entirely  too  elementary,  and  to  cover  points  on  which  instruc- 
tions are  unnecessary,  it  is  my  experience  that  mistakes  in  these 
simple  matters  are  by  no  means  confined  to  beginners. 

Field  geologists,  and  particularly  students  using  this  book,  are 
cautioned  against  its  abuse.  Directions  for  making  and  record- 
ing observations  and  for  the  use  of  the  schedules  are  intended 
to  insure  thoroughness  and  system,  not  to  relieve  the  observer 
of  the  necessity  for  thought.  It  would  be  a  misfortune  if  they 
should  hamper  originality  or  reduce  the  work  to  a  merely  mechan- 
ical process. 

013 


iv  PREFACE 

The  work  of  the  field  geologist  presents  great  diversity,  and 
while  the  more  common  types  which  will  be  encountered  in  North 
America  are  provided  for  in  the  following  instructions,  all  con- 
ditions cannot  be  foreseen,  and  the  geologist  must  modify  methods 
•  and  adapt  them  to  the  particular  needs  of  his  work.  This  is 
notably  true  in  regions  difficult  of  access,  or  where  unusual  obsta- 
cles to  travel  and  observation  must  be  overcome,  as  in  parts  of 
Canada  and  Alaska  and  most  tropical  regions.  Special  methods 
must  be  devised  to  meet  such  special  conditions,  and  the  geologist's 
success  will  be  proportional  to  his  adaptability. 

For  the  material  included  in  a  manual  of  this  kind  no  great 
amount  of  originality  can  be  claimed.  It  is  necessarily  in  large 
measure  a  compilation.  Suggestions  regarding  the  matter  to  be 
included  and  the  manner  of  treatment,  have  been  invited  from 
my  colleagues,  and  these  suggestions  have  been  freely  used.  In 
the  preparation  of  the  schedules  in  particular,  has  valuable  assist- 
ance been  given  by  those  especially  familiar  with  the  subjects 
treated.  Specific  acknowledgment  for  such  assistance  is  given 
on  subsequent  pages. 

C.   W.  HAYES. 

WASHINGTON,  D.  C.,  Feb.  22,  1909. 


CONTENTS 

PART   I 

GENERAL  INSTRUCTIONS 

PAGH 

PRE-REQUISITES  FOR  A  FIELD  GEOLOGIST 1 

Physical  and  Mental  Qualities 1 

Training 2 

CLASSIFICATION  OF  SURVEYS 3 

Official  Surveys 3 

Educational  Surveys 3 

Private  Economic  Surveys 4 

RELATIONS  TO  THE  PUBLIC 5 

PREPARATION  FOR  FIELD  WORK 6 

Organization 6 

Purpose  of  the  Work 6 

Previous  Work 10 

Topographic  Data 10 

Miscellaneous  Information 11 

FIELD  OUTFIT 11 

Instruments 11 

Notebooks 15 

Stationery  Box 16 

Personal  Outfit 16 

Camp  Subsistence 17 

Discipline 19 

FIELD  OBSERVATIONS 19 

Essential  Qualities 19 

Preliminary  Reconnaissance 20 

Work  of  Assistants 20 

ESTIMATES  OF  DISTANCE,  ETC 21 

HORIZONTAL  MEASUREMENTS 21 

Pacing 22 

Revolutions  of  a  Wheel 22 

Tape  Line 22 

Stadia 23 

V 


vi  CONTENTS 

PA<SE 

ANGULAR  MEASUREMENTS 23 

VERTICAL  MEASUREMENTS 24 

Aneroid 24 

Hand  Level 25 

Wye  Level 26 

Telescope  with  Vertical  Circle 26 

DETERMINATION  OF  THICKNESS  OF  BEDS 27 

DETERMINATION  OF  DEPTH  OF  BEDS     32 

DETERMINATION  OF  FAULTS 34 

Dip  of  Fault  Plane 34 

Angle  of  Intersection  with  Oblique  Vertical  Plane 36 

PERCENT  AND  ANGULAR  INCLINATION.     37 

FORM  OF  OUTCROP 37 

TABLES  AND  FORMULAS 43 

WRITTEN  NOTES 44 

MAP  NOTES 47 

GRAPHIC  NOTES 49 

Sketches 49 

Photographs 51 

TRAVERSE  NOTES 52 

Notebook  Traverse 52 

Sketching-case  Traverse 55 

Map  Traverse 57 

PLANE-TABLE  NOTES 57 

PROFILE  NOTES 61 

LAND-CLASSIFICATION  SURVEYS 63 

MINK  SURVEYS 66 

COLLECTIONS 70 

Purpose 70 

Numbering  and  Labeling 70 

Rocks 71 

Minerals 73 

Ore  Specimens 73 

Road  Materials 74 

Coal 75 

Fossils 78 

•    Packing 81 

CHEMICAL  ANALYSES 81 

GEOLOGIC  NOMENCLATURE 82 

PERMISSION  TO  PUBLISH £4 


CONTENTS                        ,  YU 
PART   II 

INSTRUCTIONS  FOR  SPECIAL  INVESTIGATIONS 

PAGE 

PURPOSE  OF  SCHEDULES. 86 

DESCRIPTION  AND  INTERPRETATION  OF  LAND  FORMS 87 

PETROLOGIC  OBSERVATIONS 90 

Igneous  Rocks 90 

Character  of  the  Rock 91 

Mode  of  occurrence 91 

Relations  of  Rocks 91 

Effusive  Rocks. 92 

Metamorphism 92 

Decomposition 92 

Pyroclastic  Rocks 93 

Summary 94 

Sedimentary  Rocks 95 

Clastic  Rocks 95 

Petrographic  Character 95 

Source  of  Materials 96 

Transportation  and  Deposition 96 

Fossils 97 

Character  of  Particles 97 

Texture 98 

Bedding 98 

Color 98 

Markings 98 

Cement 99 

Chemical  and  Organic  Sediments 99 

Summary 100 

Metamorphic  Rocks 101 

General  Observations 101 

Summary 102 

OBSERVATIONS  IN  STRUCTURAL  GEOLOGY 103 

For  Immediate  Field  Purposes 103 

For  Drafting  Purposes 103 

For  Historical  Purposes ^ 104 

GLACIERS  AND  GLACIAL  DEPOSITS 105 

Existing  Mountain  Glaciers 105 

Earlier  Mountain  Glaciation 106 

Pleistocene  Continental  Glaciation 106 


viii  CONTENTS 

PAGE 

INVESTIGATION  OF  PRECIOUS  AND  SEMIPRECIOUS  METALLIFEROUS 

DEPOSITS 109 

Openings  in  Rocks 109 

Simple  Fissure  Fillings 1 10 

Replacement  Veins 110 

Replacement  Deposits  of  Contact-metamorphic  Origin Ill 

Mineralogical  Study 112 

Secondary  Enrichment 113 

Pay  Shoots 113 

Commercial  and  Metallurgical  Considerations 114 

INVESTIGATION  OF  PLACER  DEPOSITS 114 

INVESTIGATION  OF  OIL  AND  GAS  FIELDS 116 

SCHEDULES 117 

Pure  Geology: 

Description  and  Interpretation  of  Land  Forms 118 

Petrology 120 

Structure 122 

Glaciers  and  Glacial  Deposits 124 

Applied  Geology: 

Precious  and  Semiprecious  Metallifeorus  Ores 126 

Placer  Deposits 128 

Iron  Ores,  Ocher,  Manganese  Ore,  and  Bauxite 130 

Stone — (A)  Sedimentary  Rocks;    (B)  Igneous  Rocks.  ...  132 

Road  Materials— (A)  Rock;    (B)  Gravel 136 

Cement  Materials  and  Lime 139 

Clay. 141 

Sand  and  Gravel 143 

Coal 145 

Oil  and  Gas 147 

APPENDIX , 149 


ILLUSTRATIONS 


1.  Brunton  Pocket  Transit 12 

2.  Geological  Hammers 13 

3.  Instrument  Belt 15 

4.  Diagram  Illustrating  Determination  of  Thickness  of  Beds  by 

Trigonometric  Method 27 

5.  Diagram  for  Use  in  Determination  of  Thickness  of  Beds  by 

Graphic  Method 29 

6.  Diagram  Illustrating  Determination  of  Thickness  of  Beds  by 

Construction  Method 32 

7.  Diagram   Illustrating   Determination   of   Depth   of   Beds   by 

Trigonometric  Method 33 

8.  Diagram  Illustrating  Determination  of  Dip  of  Fault  Plane. .  .  35 

9.  Diagram  Illustrating  Determination  of  Angle  of  Intersection 

of  Fault  Plane  with  Vertical  Plane  Oblique  to  Strike  of 

Fault 37 

10.  Diagram  Illustrating  Form  of  Outcrop 40 

11.  Diagram  Illustrating  Circular  Functions 42 

12.  Right  Triangle 42 

13.  Oblique  Triangle 42 

14.  Diagram  Illustrating  Subdivision  of  Map  for  Reference  Num- 

bers   45 

15.  Example  Illustrating  Notebook  Traverse 54 

16.  Topographic  Sketching  Case 56 

17.  Diagram  Illustrating  Triangle  of  Error 60 

18.  Example  Illustrating  Profile  Notes facing  p.  63 

iz 


HANDBOOK    FOR    FIELD    GEOLOGISTS 


PART  I 

GENERAL  INSTRUCTIONS 
PRE-REQUISITES  FOR  A  FIELD  GEOLOGIST 

Physical  and  mental  qualities.  To  insure  even  a  moderate 
degree  of  success  as  a  field  geologist  one  must  possess  certain 
physical  and  mental  qualities,  the  lack  of  which  may  be  in  no 
wise  to  one's  discredit  and  may  involve  no  particular  disability 
in  many  other  professions.  It  is  well  therefore  to  determine  in 
advance  of  the  long  apprenticeship  required  whether  or  not  the 
candidate  possesses  these  necessary  pre-requisites.  A  respon- 
sibility not  always  realized  rests  upon  teachers  of  geology  to 
explain  fully  to  their  students  the  requirements  of  the  profession, 
and  to  divert  from  it  those  who  are  manifestly  lacking  in  the 
qualities  essential  for  success. 

The  first  qualification  is  a  good  physique  and  a  strong  con- 
stitution, for  sooner  or  later  severe  and  long-continued  physical 
exertion  will  be  required,  and  a  defect  in  ability  to  sustain  this 
exertion  will  be  a  serious  handicap. 

The  second  is  adaptability.  Few  occupations  present  so  wide 
a  diversity  in  conditions  under  which  work  must  be  carried  on 
as  that  of  the  field  geologist.  His  surroundings  may  vary  all 
the  way  from  the  luxuries  of  a  summer  resort  hotel  to  the  bare 
necessities  which  he  can  pack  on  his  back,  and  he  must  be  able 
to  adapt  himself  with  equal  readiness  to  either  extreme.  If  one 
cannot  so  adapt  himself,  but  is  dependent  on  any  particular  kind 
of  surroundings,  he  should  abandon  the  idea  of  becoming  a  field 


2  GENERAL  INSTRUCTIONS 

geologist,   for  he  will  find  the  occupation  extremely  unsatisfac- 
tory. 

A  geologist  must  possess  a  practical  knowledge  of  horseman- 
ship, of  boating,  and  of  general  woodcraft,  so  that  he  will  be 
equally  at  home  in  the  saddle,  in  the  canoe,  or  on  foot  in  a  track- 
less forest.  One  is  fortunate  who  has  already  acquired  this 
practical  knowledge,  but  if  he  does  not  possess  it  he  must  be 
sure  that  he  has  an  aptitude  for  acquiring  it  quickly. 

Training.  It  is  questionable  if  geology  can  be  regarded  as 
a  distinct  science,  in  the  same  sense  as  chemistry  or  physics. 
More  properly,  it  is  the  application  of  a  number  of  special  sciences 
to  the  solution  of  a  particular  class  of  problems.  It  follows  that 
the  best  preparation  for  geologic  work  is  a  thorough  grounding 
in  these  fundamental  sciences,  particularly  chemistry,  physics, 
zoology,  and  botany.  Mathematics  and  modern  languages  are 
also  essential.  The  student  who  is  thoroughly  trained  in  the 
principles  of  these  sciences  will  readily  grasp  their  special  appli- 
cation and  will  have  a  sound  basis  on  which  to  build  up  the  struc- 
ture of  geologic  facts  and  theories  to  be  acquired  in  the  field. 
The  student  is  therefore  advised  to  plan  his  college  and  univer- 
sity work  so  as  to  acquire  this  fundamental  training,  if  necessary, 
even  at  the  expense  of  certain  geologic  courses  which  deal  with 
subjects  that  can  be  much  better  covered  in  connection  with 
subsequent  field  work.  If  he  continues  in  geology  as  a  profes- 
sion, he  will  have  abundant  opportunity  to  acquire  geologic 
facts,  but  he  will  probably  have  neither  opportunity  nor  time 
to  study  chemistry  or  physics  after  leaving  college. 

It  should  be  clearly  understood  that  this  advice  is  addressed 
only  to  those  who  expect  to  become  professional  geologists;  it 
certainly  does  not  apply  to  students  who  expect  to  follow  other 
lines  of  pure  or  applied  sciences,  or  who  are  taking  scientific  studies 
for  the  sake  of  the  breadth  of  culture  which  they  alone  can  give. 

Second  in  importance  only  to  a  thorough  grounding  in  the 
physical  sciences  is  ability  to  write  clear  and  concise  English. 
Although  the  application  of  this  part  of  a  geologist's  training 
will  come  chiefly  in  the  presentation  of  his  results,  it  is  so  neces- 
sary a  complement  to  successful  field  work  that  it  must  be  regarded 
as  an  essential  pre-requisite.  It  is  assumed  that  the  successful 


CLASSIFICATION    OF    SURVEYS  3 

geologist  will  be  a  clear  and  logical  thinker,  and  it  should  be 
equally  a  matter  of  course  that  his  writing  will  be  clear  and  logical. 
The  highest  literary  style  can  be  attained  by  a  few  only,  but 
clearness  is  within  the  reach  of  all  who  are  willing  to  take  the 
pains  necessary  for  acquiring  it. 


CLASSIFICATION    OF   SURVEYS 

Official  surveys.  By  far  the  larger  part  of  the  systematic 
work  in  field  geology  in  North  America  is  done  under  the  aus- 
pices of  official  surveys.  Federal  surveys  are  maintained  in 
Canada,  the  United  States,  and  Mexico;  also  provincial  or  state 
surveys  in  Ontario  and  in  thirty-five  of  the  states.*  The  form 
and  functions  of  these  organizations  varies  somewhat  widely, 
but  nearly  all  are  engaged  in  some  form  of  field  work,  although 
a  few  are  primarily  bureaus  of  information. 

The  degree  of  specialization  in  these  organizations  depends 
chiefly  on  the  number  of  men  in  their  scientific  force,  and  natu- 
rally is  greatest  in  the  federal  surveys.  The  need  for  specialists 
in  many  of  the  state  surveys  is  met  in  a  measure  by  the  occa- 
sional employment  of  university  professors.  The  larger  organ- 
izations, both  state  and  federal,  are  under  the  classified  civil 
service  regulations,  and  in  these,  appointments  are  made  only 
after  competitive  examination  or  other  impartial  test  of  fitness. 

Appointments  are  usually  made  to  the  lower  grades  and  service 
as  an  assistant  for  a  period  of  one  to  three  years  is  required  before 
the  geologist  is  given  independent  work.  The  length  of  this 
apprenticeship  depends  largely  upon  previous  training,  and  it 
is  therefore  highly  important  for  the  beginner  to  become  early 
and  thoroughly  familiar  with  the  best  field  methods. 

Educational  surveys.  Most  teachers  of  geology  recognize 
that  certain  parts  of  the  subject  can  be  properly  taught  only  in 
the  field,  and  therefore  include  field  courses  as  a  regular  part  of 
their  instruction.  This  is  generally  confined  of  necessity  to  the 
immediate  vicinity  of  the  institution,  but  occasionally  a  more 

*  Information  concerning  the  organization  and  personnel  of  these  official 
surveys  is  given  in  Appendix  I  to  this  volume. 


4  GENERAL    INSTRUCTIONS 

remote  field  is  selected,  and  systematic  work  is  carried  on  which 
may  result  in  definite  contributions  to  geologic  knowledge.  In 
selecting  a  locality  for  such  educational  work  several  considera- 
tions should  be  kept  in  mind.  The  region  chosen  should  present 
^some  diversity  in  geologic  phenomena,  but  should  not  be  so 
complicated  as  to  prevent  the  beginner  from  reaching  definite 
results  through  his  own  exertions.  He  should  not  have  too 
early  impressed  upon  him  the  uncertainty  which  attaches  to 
many  geologic  conclusions,  but  should  acquire  a  proper  degree 
of  confidence  in  his  results.  The  area  should  not  be  too  large 
for  thorough  work,  nor  should  it  be  so  small  that  the  student 
will  fail  to  have  impressed  upon  him  the  important  fact  that, 
later,  quantity  as  well  as  quality  will  be  demanded  of  him.  It 
is  generally  best  to  require  the  construction  of  a  topographic  base 
on  which  to  represent  the  geology,  even  if  the  region  selected 
is  already  mapped,  for  the  ability  to  construct  a  good  topographic 
map  is  a  fundamental  part  of  a  geologist's  training. 

The  beginner  learns  most  from  his  own  mistakes,  but  only 
when  he  is  obliged  to  correct  them  himself.  It  is  essential,  there- 
fore, that  while  he  should  be  thrown  early  on  his  own  resources, 
his  results  should  be  most  carefully  checked  by  some  one  more 
experienced.  The  practice  of  sending  out  untrained  men  to  do 
even  the  simplest  forms  of  field  work  without  supervision,  and 
accepting  their  results  without  thorough  examination,  is  equally 
bad  for  geology  and  for  the  geologist. 

Private  economic  surveys.  Mining  operators  are  rapidly 
coming  to  a  fuller  appreciation  of  the  intimate  relation  between 
geologic  conditions  and  occurrence  of  ore  bodies.  The  demands 
for  geologic  surveys  of  mining  properties  are  therefore  increas- 
ing. This  is  especially  true  with  the  larger  and  better  organized 
companies.  Such  surveys  differ  in  no  important  respect  from 
certain  of  those  made  by  government  organizations,  except  that 
they  are  generally  confined  to  a  smaller  territory,  and  the  eco- 
nomic results  are  not  immediately  made  public.  Surveys  of  this 
kind  are  in  progress  in  connection  with  the  development  of  coal, 
oil,  iron-ore,  and  the  metalliferous  ores  in  many  parts  of  the 
country,  and  the  field  methods  applicable  are  exactly  the  same 
as  in  public  surveys  of  similar  scope  and  purpose. 


CLASSIFICATION    OF    SURVEYS  5 

Relations  to  the  public.  The  movements  of  the  field  geol- 
ogist are  calculated  to  excite  a  lively  curiosity  in  the  mind  of 
the  onlooker,  and  the  geologist  must  expert  to  be  assailed  by  a 
great  number  of  questions.  It  is  generally  advisable  to  take  the 
necessary  time  and  trouble  to  explain  to  any  one  making  serious 
inquiry  exactly  what  is  the  object  of  the  work.  This  is  of  course 
essential  where  the  survey  is  official  and  carried  on  at  govern- 
ment expense.  The  opportunity  to  educate  the  people  of  a 
region  in  which  work  is  being  done  to  an  appreciation  of  the 
nature  and  importance  of  geologic  surveys  should  be  utilized 
so  far  as  possible. 

Objection  is  sometimes  made  to  entry  on  private  property,  but 
the  geologist  will  generally  be  able  to  overcome  such  objection 
by  an  explanation  of  the  character  and  object  of  his  work.  The 
most  strenuous  objection  can  often  be  changed  into  hearty 
cooperation  by  the  exercise  of  a  little  tact. 

Laws  have  been  enacted  in  Arizona,  California,  Illinois,  Maine, 
Montana,  New  York,  Ohio,  Pennsylvania,  and  Washington, 
granting  authority  to  officials  of  the  State  and  Federal  Surveys 
to  enter  on  private  property  when  engaged  in  official  work.  Even 
in  these  states,  however,  the  policy  of  conciliation  is  generally 
preferable  to  an  insistence  on  the  legal  right. 

All  field  geologists,  particularly  those  engaged  in  economic 
work,  should  recognize  their  obligations  in  relation  to  the  infor- 
mation which  they  acquire  in  connection  with  their  work.  Any 
appearance  or  suspicion  of  favoritism  in  giving  out  the  results 
of  official  surveys  should  be  avoided,  and  all  who  are  interested 
in  the  results  of  the  work  should  be  assured  of  fair  and  equal  par- 
ticipation in  any  benefits  to  be  derived  from  them.  It  is  usually 
regarded  as  proper  and  permissible  to  communicate  orally  to 
the  owner  or  manager  of  a  mineral  property  during  the  progress 
of  its  investigation  such  information  regarding  the  geology  of 
that  property  as  may  be  of  value  in  its  development,  but  written 
statements  should  be  avoided  lest  they  be  used  for  promoting 
or  unduly  enhancing  values. 

Information  of  a  confidential  character,  such  as  drill  records, 
mine  maps,  statistics  of  production  and  analyses,  supplied  by 
private  parties  or  corporations,  should  be  most  carefully  guarded 


6  GENERAL    INSTRUCTIONS 

and  used  strictly  in  accordance  with  the  conditions  stipulated  by 
the  persons  furnishing  it. 


PREPARATION   FOR   FIELD   WORK 

Organization.  The  party  is  the  natural  administrative  unit 
in  an  organization  engaged  in  field  work,  and  there  should  be  no 
room  for  misunderstanding  as  to  who  is  in  charge  of  the  party, 
and  hence  responsible  for  its  conduct.  The  chief  of  party  should 
be  furnished  written  instructions  which  are  clear  and  definite 
as  to  essentials,  particularly  location,  scope,  and  purpose  of  the 
work.  Since  contingencies  which  cannot  be  foreseen  are  sure 
to  arise,  it  is  better  to  leave  a  certain  amount  of  discretion  with 
the  party  chief,  rather  than  to  hamper  him  with  minute  instruc- 
tions. He  should  be  impressed  with  the  fact  that  results  are 
required,  and  that  they  must  be  proportionate  in  quantity  and 
quality  to  the  expenditure.  After  receiving  his  instructions  the 
chief  of  party  should  adhere  to  them  until  they  are  replaced  or 
modified  by  other  written  instructions,  and  in  no  case  should  he 
make  any  material  change  on  oral  instructions  from  any  source. 
If  the  field  work  is  limited  by  the  amount  of  money  which  can 
be  expended  on  it,  the  exact  allotment  should  be  known  in  advance, 
in  order  that  definite  units  may  be  brought  to  completion  within 
the  given  limitations. 

Scientific  and  technical  field  assistants  will  generally  be  selected 
and  employed  in  advance  by  the  proper  administrative  officer, 
but  the  chief  of  party  should  be  consulted  in  such  selection  and 
their  personal  and  scientific  qualifications  should  be  satisfactory 
to  him. 

The  selection  and  employment  of  necessary  laborers,  including 
cooks,  teamsters,  packers,  etc.,  should  be  left  to  the  chief  of  party. 
As  the  efficiency  of  the  party  is  largely  dependent  on  the  capacity 
and  willingness  of  the  laborers,  care  should  be  exercised  in  their 
selection.  Excellent  results  have  been  obtained  in  many  cafees 
by  selecting  college  students  for  these  positions. 

Purpose  of  the  work.  Obviously,  the  first  step  in  prepara- 
tion for  the  field  is  a  determination  of  the  exact  purpose  of  the 


PREPARATION    FOR    FIELD    WORK  7 

work.  Upon  this  will  depend  the  character  of  field  methods 
and  outfit  adopted.  These  will  vary  widely  in  accord  with  vary- 
ing circumstances.  The  purpose  of  the  work  may  be  a  detailed 
study  of  a  small  area  or  a  rapid  reconnaissance  of  a  very  large 
one.  It  may  involve  operations  from  a  single  station  or  the 
collection  of  information  during  rapid  travel  through  the  coun- 
try, and  with  no  possibility  of  departing  from  a  single  route. 
The  object  may  be  purely  economic  or  purely  scientific,  or  it  may 
involve  both  considerations  in  all  proportions. 

Field  work  may  be  classified  as  follows: 

1.  Areal,  structural,  and  stratigraphic  geology,  with  incidental 
study  of  economic  mineral  deposits. 

The  primary  purpose  of  this  class  of  work  is  the  preparation 
of  a  geologic  map  which,  with  the  accompanying  structure  sec- 
tions, shall  show  the  distribution  of  geologic  formations  at  the 
land  surface,  and  their  attitude  and  position  below  the  surface. 
It  may,  at  the  same  time,  cover  a  comprehensive  study  of  the 
mineral  resources  or  may  be  simply  intended  to  furnish  a  basis 
for  further  study  of  the  economic  geology,  by  showing  the  surface 
and  underground  distribution  of  the  formations  with  which  the 
mineral  deposits  are  known  to  be  associated.  The  character  of 
these  deposits  will  influence  the  degree  of  refinement  with  which 
the  work  must  be  done  and  the  points  to  which  special  attention 
is  directed.  For  example,  if  the  region  contains  coal  or  oil,  it 
is  highly  important  that  the  underground  structure  be  accurately 
determined  so  that  the  depth  to  a  particular  stratum  may  be 
predicted  within  a  few  feet  at  any  point  on  the  area  mapped. 
Data  from  which  the  underground  contours  of  a  selected  stratum 
may  be  constructed  must  therefore  be  secured  in  addition  to 
those  required  for  structure  sections.  If,  on  the  other  hand, 
the  region  contains  only  such  deposits  as  are  worked  at  the  sur- 
face, as  limonite  iron-ore,  building  stone,  etc.,  the  underground 
structure  is  less  important,  but  it  is  necessary  to  map  outcrops 
of  particular  beds  very  accurately. 

The  scale  on  which  the  results  of  field  work  are  to  be  published 
should  be  considered  in  advance,  and  the  degree  of  refinement 
suited  to  this  scale.  It  will  often  be  necessary  to  work  certain 
parts  of  the  area  in  greater  detail  than  can  be  shown  on  the  final 


8  GENERAL   INSTRUCTIONS 

map,  in  order  to  determine  the  key  to  intricate  structural  prob- 
lems, but  considerations  of  economy  and  the  practicability  of 
cartographic  representation  fix  a  rigid  limit  upon  such  detailed 
work.  On  the  other  hand,  the  work  should  be  as  nearly  up  to 
the  scale  as  the  limitations  of  time  and  allotment  for  the  work 
permit.  In  short,  the  field  geologist  must  avoid  the  opposite 
extremes  of  becoming  lost  in  a  mass  of  detail  which  cannot  be 
represented,  and  indulging  in  generalizations  which  seriously 
detract  from  the  value  of  the  map.  The  proper  adjustment  of 
the  field  work  between  these  extremes  is  secured  only  by  experi- 
ence and  intelligent  consideration  of  the  purpose  of  the  work. 

The  great  variety  of  uses  to  which  maps  resulting  from  this 
flass  of  field  work  will  be  put  should  be  kept  in  mind.  They 
should  be  adapted  to  educational  purposes,  to  the  economical 
and  conservative  development  of  mineral  deposits,  to  the  deter- 
mination of  water  supply,  both  surface  and  underground,  to 
the  location  of  roads  and  road  materials,  to  the  study  of  character 
and  distribution  of  soils,  to  the  study  of  forests  and  reforestation, 
the  classification  of  public  lands,  etc. 

2.  Economic  geology  with  incidental  study  of  areal,  structural, 
and  stratigraphic  problems. 

The  primary  purpose  of  this  class  of  work  is  the  determination 
of  the  geologic  relations  of  particular  mineral  deposits.  The 
study  of  areal  distribution  of  formations  and  underground  struc- 
ture is  incidental  to  this  object,  though  generally  essential.  The 
area  covered  by  such  work  is  generally  more  restricted  than  in 
the  former  class,  and  the  work  is  done  in  greater  detail  and  on 
a  larger  scale.  In  case  of  mineral  deposits  having  wide  distri- 
bution, as  coal,  the  scale  of  the  work  and  the  methods  which 
should  be  employed  do  not  differ  materially  from  the  first  class 
except  that  more  attention  is  given  to  the  study  of  the  coal  itself, 
to  its  composition  and  its  variation  from  place  to  place,  and  to 
all  of  the  conditions  which  will  affect  its  economical  develop- 
ment. 

In  case  of  metalliferous  ore&,  particularly  of  gold,  silver,  and 
copper,  the  area  within  which  the  geology  is  to  be  studied  is 
usually  confined  to  a  few  square  miles,  but  within  these  limits 
it  must  be  examined  in  an  extremely  detailed  manner  and  all 


PREPARATION    FOR    FIELD    WORK  9 

possible  lines  of  evidence  followed,  both  on  the  surface  and  under- 
ground. In  such  work  no  details  of  structure  or  petrology  can 
be  overlooked,  for  it  is  upon  these  that  conclusions  as  to  genesis 
and  extent  of  the  ores  must  rest. 

The  work  of  the  economic  geologist  should  be  clearly  differ- 
entiated from  that  of  the  mining  engineer  who  is  concerned 
primarily  with  determinations  of  amount  and  value  of  ore  in 
the  deposit  and  methods  of  economical  exploitation.  Both 
functions  may  be  performed  by  the  same  person,  but  they  should 
be  kept  entirely  distinct. 

3.  Investigation  of  the  geology  of  mineral  deposits. 

Work  of  this  class  is  of  two  kinds:  first,  the  study  of  ore 
deposits  in  districts  where  the  areal  and  structural  geology  has 
already  been  done,  and  second,  general  study  of  some  particular 
kind  of  deposits.  The  former  differs  in  no  way  from  Class  2  above, 
except  that  it  is  confined  strictly  to  the  mineral  deposits,  while 
the  latter  covers  so  many  widely  separated  deposits  that  oppor- 
tunity is  generally  afforded  only  for  a  hasty  reconnaissance  of 
the  surrounding  geology  without  detailed  mapping. 

4.  Investigation  of  paleontologic,   petrographic   and    stratigraphic 
geology. 

The  paleontologist  and  petrographer  are  no  longer  content,  as 
formerly,  to  work  only  in  the  labroatory,  but  appreciate  the  neces- 
sity of  field  observation.  Their  work  can  be  done  most  advan- 
tageously in  immediate  cooperation  with  the  work  of  the  field 
geologist,  for  these  specialists  furnish  the  standards  for  classi- 
fication and  correlation  on  which  the  field  geologist  must  rely. 
It  is  highly  desirable,  therefore,  that  the  correct  standards  should 
be  established  in  the  field  by  means  of  preliminary  paleontologic 
and  petrographic  determinations. 

In  addition  to  the  above,. and  independently  of  areal  surveys, 
studies  are  desirable  of  particular  localities  where  important  strati- 
graphic  sections  or  groups  of  rocks  occur.  These  are  chiefly 
contributory  to  pure  geology,  though  they  may  have  important 
economic  applications. 

5.  Investigation  of  glacial  and  physiographic  geology. 

While  the  study  of  glacial  deposits  is  in  large  measure  purely 
areal,  the  methods  and  criteria  employed  are  so  specialized  that 


10  GENERAL    INSTRUCTIONS 

it  is  placed  in  a  separate  class.  In  addition  to  the  classification 
based  on  character  and  origin  of  the  materials  making  up  glacial 
formations,  surface  form  is  more  important  than  in  other  classes 
of  work,  and  glacial  geology  therefore  merges  into  physiography, 
in  which  form  is  the  principal  factor  considered.  It  is  frequently 
desirable  to  have  the  glacial  and  physiographic  geology  worked 
separately  from  the  areal  and  structural  geology  of  the  hard 
rocks.  This  is  a  degree  of  specialization  which  is  not  always 
practicable,  but  is  productive  of  the  best  results. 

Previous  work.  Before  taking  the  field  the  chief  of  party  (and 
his  assistants  also,  if  possible)  should  familiarize  himself  with 
previous  geologic  work,  published  and  unpublished,  relating  to 
the  region.  He  should  endeavor  to  find  out  the  amount  of  ascer- 
tained fact,  as  distinguished  from  interference,  represented  on 
each  map.  Such  previous  work  should  be  utilized  to  the  utmost, 
but  the  geologist  should  guard,  on  the  one  hand,  against  following 
former  conclusions  slavishly  and,  on  the  other,  against  going  out 
of  his  way  to  prove  his  predecessor  in  the  wrong. 

If  geologic  maps  of  the  region  have  been  published,  an  extra 
copy  of  each  should  be  obtained,  if  possible,  and  so  mounted  as 
to  be  convenient  for  use  in  the  field.  It  is  not  generally  desirable 
to  carry  a  large  amount  of  literature  into  the  field,  but  exception 
should  be  made  in  favor  of  reports  to  which  frequent  reference 
will  be  made  during  the  progress  of  the  work. 

Topographic  data.  All  available  maps  relating  to  the  region 
to  be  studied  should  be  procured.  Atlas  sheets  for  field  use  should 
be  sectioned  and  mounted  on  cloth  for  folding  or  on  leaves  for 
insertion  in  the  notebook.  If  notes  are  placed  directly  on  the 
map  the  latter  method  is  preferable,  as  there  is  less  liability  of 
loss.  A  convenient  method  of  protecting  from  injury  a  folded 
map,  mounted  or  unmounted,  is  to  carry  it  in  a  transparent 
celluloid  pocket  which  may  be  fastened  on  the  inside  of  the  note- 
book cover.  By  proper  folding,  any  part  of  the  map  can  thus 
be  consulted  without  removing  it  from  the  case.  A  few  extra 
copies  of  the  atlas  sheets  covering  quadrangles  on  which  work 
is  to  be  done  should  be  taken  into  the  field.  If  no  topographic 
map  is  available,  or  if  the  map  is  known  to  be  inadequate  or  inac- 
curate, special  efforts  should  be  made  to  procure  all  available 


FIELD    OUTFIT  11 

topographic  data,  such  as  railroad  locations  and  profiles,  ditch 
surveys,  private  mining-district  maps,  land  office  township  plats, 
etc.  Many  of  these  data  must  be  obtained  by  correspondence, 
which  requires  time  and  should  not  be  postponed  until  the  eve 
of  taking  the  field. 

Miscellaneous  information.  If  the  field  to  which  a  chiei 
of  party  is  assigned  is  a  new  one  he  should,  before  leaving  the 
office,  gain  all  information  possible  concerning  climate,  vegeta- 
tion, roads  and  trails,  inhabitants,  supply  points,  railroad,  stage, 
mail,  express,  and  telegraphic  facilities,  and  all  other  matters 
which  will  have  a  bearing  on  the  method  of  carrying  on  the  work 
and  affect  its  economy  and  efficiency.  Much  of  this  information 
can  usually  be  obtained  by  conference  in  the  office  with  topog- 
raphers and  others  familiar  with  the  region,  but  some  must 
generally  be  secured  through  correspondence. 


FIELD    OUTFIT 

Instruments.  For  ordinary  geologic  field  work  the  necessary 
equipment  of  instruments  is  neither  elaborate  nor  expensive. 
The  following  list  includes  all  which  will  be  needed  under  ordinary 
conditions.  They  are  arranged  in  order  of  importance. 

Compass.  Should  be  supplied  with  a  clinometer  and  movable 
circle  for  adjustment  for  magnetic  declination.  The  Gurley 
aluminum  geologic  compass  with  staff  socket,  is  best  suited  for 
many  kinds  of  work,  particularly  for  tracing  land  lines  where 
considerable  accuracy  is  required.  The  Brunton  pocket  transit 
shown  in  Fig.  1,  is  compact,  convenient,  and  accurate.  It  is 
adapted  to  a  variety  of  purposes,  and  is  probably  the  best  type 
for  general  geologic  work.  It  can  be  used  as  a  prismatic  or  sight- 
ing compass,  clinometer  and  hand  level,  and  is  especially  adapted 
for  mine  surveys.  In  regions  where  there  is  strong  local  mag- 
netic attraction,  a  dial  compass  is  required,  with  graduation  for 
the  particular  latitude  at  which  it  is  to  be  used. 

Hammer.  Should  weigh  from  one  to  one  and  a  quarter  pounds 
without  handle.  The  type  shown  in  Fig.  2a,  is  the  one  adapted 
to  most  purposes,  though  some  geologists  prefer  a  chisel  point, 


12 


GENERAL    INSTRUCTIONS 


Fig.  2$,  instead  of  the  pick.     This  is  useful  in  soft  rocks  or  where 
digging  must  be  done,  as  on  a  coal  crop.     Only  the  best  steel 


FIG.  1. — Brunton  pocket-transit. 


should  be  used,  and  tempered  so  that  it  will  not  chip.  A  trim- 
ming hammer,  Fig.  2&  is  desirable  where  museum  specimens  are 
to  be  collected.  It  should  weigh  about  six  ounces. 


FIELD    OUTFIT 


13 


Collecting  bag.  Should  be  made  of  strong  canvas  or  leather, 
about  12X12X4  inches,  with  carrying  strap  to  pass  entirely 
around  it,  and  loops  or  hooks  to  attach  to  a  belt.  It  should  have 
a  double  back,  forming  a  pocket  for  maps  and  a  smaller  pocket 


FIG.  2.  —  Geological  hammers. 


on  the  front  for  notebook.  The  flap  should  be  ample  to  protect 
its  contents  from  rain.  A  larger  bag  will  be  needed  by  geologists 
making  fossil  collections,  and  it  should  be  provided  with  two 
shoulder  straps  for  use  as  a  knapsack. 

In  case  much  work  is  done  on  horseback,  saddle  pockets  will 


14  GENERAL    INSTRUCTIONS 

be  found  very  useful.  The  pockets  should  be  about  12X12X4 
inches,  and  one  of  them  should  be  attached  by  rings  and  snap 
hooks,  so  that  it  can  be  readily  removed  and  used  as  an  ordinary 
collecting  bag. 

Aneroid.  Should  be  selected  with  reference  to  the  region  in 
which  it  is  to  be  used,  and  should  be  the  lowest  reading  permitted 
by  the  maximum  altitude,— 3000',  5000',  10,000',  etc.  The 
aneroid  should  be  carried  in  a  snug-fitting  leather  case  with  loops 
for  belt,  or  in  shirt  pocket  with  buttoned  flap,  never  loose  in  coat 
pocket  or  collecting  bag,  or  by  a  strap  over  the  shoulder. 

Hand  level.  Needed  to  supplement  the  aneroid  where  accurate 
stratigraphic  work  is  to  be  done.  For  ordinary  work  a  Brunton 
pocket  transit  will  answer,  but  if  much  leveling  is  done  a  Locke 
or  Abney  level  should  be  provided.  The  Abney  level  may  also 
be  used  as  a  clinometer  and  for  determination  of  vertical  angles. 
As  explained  on  page  25,  it  may  be  desirable,  under  certain  con- 
ditions, to  use  a  telescopic  hand  level  with  staff  socket. 

Field  glass.  Zeiss  anistigmatic  is  preferred,  on  account  of 
compactness,  and  the  monocular  is  preferable  to  the  binocular 
for  the  same  reason.  Very  little  use  will  be  made  of  field  glasses 
in  a  region  of  low  relief,  particularly  if  forested.  They  are  needed 
in  high  or  unforested  regions. 

Camera.  Should  fold  compactly.  Most  field  purposes  are 
served  by  a  4JX5^,  unless  the  geologist  is  a  skilled  photographer. 
Larger  sizes  should  always  be  used  with  tripod.  Roll  films  or 
film  packs  should  be  used  unless  the  facilities  for  handling  glass 
plates  are  exceptionally  good. 

Plane  table.  Fifteen-inch  traverse  table  with  open  sight  alidade 
or  Graton  alidade  (for  description  see  page  61),  will  serve  most 
geologic  purposes.  In  exceptional  cases,  where  an  accurate 
topographic  base  is  to  be  made  by  triangulation  methods,  a  John- 
son plane  table  and  telescopic  alidade  will  be  required. 

Sketching  case.  The  Smith  case  (for  description  see  page  55), 
is  specially  adapted  for  rapid  reconnaissance,  topographic,  and 
geologic  work. 

Transit  or  Wye  level.  Needed  only  in  special  cases,  as  detailed 
survey  of  an  oil  field,  where  greater  accuracy  is  required  than 
can  be  secured  with  hand  level. 


FIELD   OUTFIT  15 

Minor  instruments.  The  geologist  should  be  supplied  with  a 
good  pocket  lense,  several  4-inch  celluloid  or  horn  protractors, 
a  50  or  100-foot  steel  or  linen  tape,  a  zigzag  jointed  5-foot  rule, 
a  tally  register,  a  set  of  colored  pencils,  and  a  supply  of  5H-8H 
drawing  pencils. 

Notebooks.  A  variety  of  notebooks  are  suited  for  field  use, 
and  the  kind  to  be  used  will  depend  on  individual  preference  and 


FIG.  3. — Instrument  belt. 

the  character  of  the  work.  The  paper  should  be  of  good  quality, 
sufficiently  tough  to  stand  hard  usage,  and  with  a  surface  suit- 
able for  both  ink  and  pencil.  For  many  purposes  accurate  quad- 
rille ruling  is  essential,  and  convenient  scales  for  both  written 
and  platted  notes  are  five  or  six  lines  to  the  inch.  For  very 
detailed  plats  on  large  scale,  as  for  mine  notes,  a  convenient  ruling 
is  in  inches  and  tenths. 


16  GENERAL    INSTRUCTIONS 

The  size  of  the  notebook  is  a  matter  of  individual  preference, 
but  experience  has  shown  that  a  page  about  5X7  inches  is  adapted 
to  most  purposes.  For  profile  notes,  described  on  page  61,  a  book 
8X10  inches  is  somewhat  more  convenient,  although  the  smaller 
page  may  be  used  nearly  as  well. 

When  observations  on  a  number  of  different  subjects  are  to 
be  recorded,  as  is  generally  the  case  in  areal  work,  a  loose-leaf 
notebook  is  recommended.  This  permits  the  classification  and 
assembling  of  notes  relating  to  a  single  subject  or  a  single  area, 
whether  made  by  one  or  several  persons.  It  is  also  recommended 
for  the  geologist  who  visits  a  number  of  widely  separated  locali- 
ties in  the  course  of  a  single  season.  The  outfit  adopted  by  the 
U.  S.  Geological  Survey  consists  of  fillers  containing  forty-eight 
leaves,  5X7  inches,  quadrille  ruled  on  one  side  to  sixths.  They 
are  bound  in  cheap  press-board  covers,  and  perforated  for  removal 
of  leaves.  Suitable  punched  holes  at  the  top  of  the  books  permit 
the  filing  of  the  leaves  in  Twinlock  binders. 

Stationery  box.  Each  party  should  be  provided  with  a  suit- 
able box  for  carrying  stationery,  maps,  notebooks,  and  instru- 
ments. A  small  steamer  trunk  with  trays  specially  arranged 
for  the  purpose  is  most  convenient. 

Personal  outfit.  Conditions  under  which  field  work  is  to  be 
carried  on  will  necessarily  determine  the  personal  outfit  with 
which  the  field  man  must  provide  himself.  He  will  naturally 
consult  his  own  taste  in  matters  of  dress,  but  certain  considera- 
tions should  be  kept  in  mind. 

(a)  The  bulk  and  weight  of  the  outfit  should  be  kept  as  low 
as  possible.  The  allowable  limit  will  be  determined  by  the 
form  of  transportation.  It  should  be  lowest  where  there  is  to 
be  much  travel  by  stage  and  private  conveyance  or  by  pack  train, 
and  may  be  higher  where  work  is  done  from  a  few  hotels  or  from 
a  camp  provided  with  wagon  transportation. 

(6)  Neatness  in  dress,  so  far  as  is  compatible  with  the  nature 
of  the  work,  is  strongly  urged  on  field  men.  This  can  best  be 
secured  by  having  clothing  specially  designed  for  field  work. 
Khaki  has  proved  highly  satisfactory  under  a  variety  of  condi- 
tions, and  samples  of  garments  made  from  this  material  and 
suited  for  field  use  may  be  inspected  in  the  office  and  ordered 


FIELD   OUTFIT  17 

from  the  maker  at  reasonable  prices.  It  should  be  remembered 
that  a  survey  is  judged  generally  throughout  the  country  by  its 
field  representatives,  and  in  personal  appearance  as  well  as  in 
other  ways  they  should  do  it  credit. 

(c)  Special  attention  should  be  given  to  shoes,  since  the  con- 
ditions of  a  man's  feet  will  materially  affect  the  amount  of  work 
he  will  accomplish.  Bedding  will  not  generally  be  furnished, 
and  the  man  who  expects  to  live  in  camp  should  supply  his  own 
Wool  blankets  of  good  quality  are  most  satisfactory  and  eco- 
nomical, and  in  malarial  regions  a  mosquito  bar  should  always 
be  used.  Folding  camp  cots  should  be  provided;  also  canvas 
bed  covers. 

(d}  The  chief,  or  some  member  of  each  party,  should  provide 
himself  with  a  small  supply  of  simple  medicines,  bandages,  etc., 
and  with  directions  for  rendering  first  aid  to  the  injured. 
This  is  especially  important  where  the  field  work  is  remote  from 
physicians  and  druggists.  The  outfit  should  include  a  hypo- 
dermic syringe  and  a  supply  of  potassium  permanganate  for 
regions  infested  with  poisonous  snakes. 

Camp  subsistence.  In  some  regions  it  is  necessary,  and  in 
others  desirable,  to  work  with  a  camp  outfit.  The  character  of 
the  outfit  must  be  varied  to  meet  the  conditions,  particularly  the 
size  of  party,  means  of  transportation,  and  character  of  work. 
It  should  contain  the  essentials  for  efficiency  and  comfort.  Unneces- 
sary hardship  should  be  avoided  as  much  as  unnecessary  luxury, 
for  both  lower  efficiency. 

Economy  in  the  purchase  and  use  of  supplies  is  expected,  though 
the  supply  should  be  abundant  and  of  good  quality.  The  sub- 
joined ration,  prepared  primarily  for  the  Alaskan  parties  of  the 
U.  S.  Geological  Survey,  has  been  used  for  a  number  of  years  and 
found  both  abundant  and  well  balanced.  It  will  be  found  useful 
in  ordering  supplies,  particularly  when  transportation  is  by  pack- 
ing, and  therefore  limited.  The  amounts  of  some  articles  will, 
of  course,  be  reduced  if  fresh  meat,  eggs,  and  vegetables  can  be 
bought  in  the  country,  and  also  if  transportation  permits  the 
carrying  of  canned  vegetables,  fruit,  and  milk. 


18  GENERAL    INSTRUCTIONS 

UNIT  RATION 
[Pounds] 

Flour  or  hard  tack 1 .000 

Cereals 179 

Beans 143 

llice 085 

Evaporated  potatoes 161 

Pea  sausage 032 

Evaporated  soup  vegetables 018 

1.618 

Bacon 716 

Butter 140 

Dried  beef 027 

Crystallized  eggs 030 

Beef-tea  capsules 002 

.915 

Sugar 251 

Tea 036 

Coffee 054 

Chocolate 018 

.359 

Onions 0054 

Lime  juice 0008 

Vinegar 0018 

Evaporated  fruit 2230 

• .231 

Salt 053 

Baking  powder 029 

.082 

Pepper 002 

Mustard 0004 

Celery  salt 0004 

Cinnamon 0004 

Ginger 0004 

Curry 0004 

.004 

3.209 

It  is  often  desirable  to  know  in  advance  the  amount  of  feed 
which  will  be  required  by  stock,  and  the  following  ration  may 
be  used  as  a  basis  for  estimates: 

UNIT  RATION  FOR  STOCK 

[Pounds] 

Oats  or  Corn.  Hay. 

Heavy  horses 12        15  18 

Light  horses 10         12  14 

Mules 8          8  12 


FIELD    OBSERVATIONS  19 

Discipline.  In  the  conduct  of  a  party  in  camp  the  chief 
should  insist  on  punctuality,  order,  and  neatness.  With  increase 
in  the  size  of  a  party  a  proper  amount  of  discipline  becomes  abso- 
lutely essential  to  efficiency.  He  should  also  insist  on  a  proper 
regard  for  health  on  the  part  of  each  member  of  his  party.  Well- 
prepared  food,  protection  from  flies  and  mosquitoes,  and  care 
in  respect  to  drinking  water  are  prime  essentials  for  health,  and 
too  much  care  cannot  be  exercised  in  these  particulars.  Camp 
sites  should  be  carefully  selected  and  the  tents  should  be  arranged 
in  a  definite  order  and  not  at  random. 


FIELD    OBSERVATIONS 

Essential  qualities.  Field  observations  should  be  thorough, 
accurate,  systematic,  and  comprehensive.  On  the  degree  in  which 
these  qualities  are  realized  will  depend  the  value  of  the  conclu- 
sions embodied  in  the  resulting  report,  and  hence  the  scientific 
standing  of  the  geologist  and  his  value  to  the  organization  employ- 
ing him.  No  geologist  achieves  perfection  in  this  particular, 
but  nothing  short  of  perfection  should  be  the  aim. 

Thoroughness  demands  and  involves  willingness  to  perform  the 
necessary  labor  required  to  get  into  close  contact  with  the  phe- 
nomena to  be  observed.  It  often  entails  foot  work  and  climbing 
where  the  temptation  is  strong  to  use  the  glasses.  It  requires 
the  same  alertness  at  the  end  of  a  long  day  as  at  its  beginning. 
The  field  geologist  should  always  bear  in  mind  the  fact  that  he 
will  probably  never  again  see  the  particular  locality  he  is  study- 
ing, and  should  therefore  aim  to  make  his  observations  so  thor- 
ough that  he  will  never  again  need  to  see  it. 

Accuracy  involves  exact  location  by  close  watch  of  the  map. 
constant  appeal  to  measurement,  minute  examination,  and  a  full 
record,  for  no  matter  how  vividly  observations  seem  fixed  in  the 
memory  at  the  time,  they  will  certainly  fade  and  become  so  con- 
fused with  others  that  their  value  will  be  reduced  to  zero  or  less. 

System  is  easy  for  some  and  difficult  for  others,  but  can  be 
cultivated  with  advantage  by  all.  To  assist  in  its  cultivation 
is  the  object  of  the  schedules  appended  to  this  volume. 


20  GENERAL    INSTRUCTIONS 

Comprehensiveness  comes  with  experience,  together  with  an 
appreciation  of  the  variety  of  phenomena  to  be  observed  and  of 
their  relations.  There  is  no  region  so  simple  as  to  present  only 
a  single  class  of  geologic  phenomena  and  the  geologist  should 
observe  all  facts  in  some  classes  (determined  by  the  main  purpose 
of  his  work)  and  some  facts  in  all  classes.  Even  if  his  work  is 
primarily  economic,  he  should  be  thoroughly  alive  to  the  purely 
scientific  problems  presented  by  the  region  and  can  generally 
study  one  or  more  such  problems  without  detriment  but  with 
probable  advantage  to  his  economic  work. 

Preliminary  reconnaissance.  On  reaching  the  field,  if  the 
geologist  is  not  already  familiar  with  its  general  relations  from 
previous  work  in  the  same  or  adjoining  regions,  he  will  find  it 
highly  profitable  to  spend  the  necessary  time  in  making  a  pre- 
liminary reconnaissance.  By  this  means  he  should  be  able  to 
outline  the  problems  to  be  investigated  and  to  determine  the  logi- 
cal order  of  procedure  for  their  solution.  A  sufficiently  definite 
idea  of  the  physiography,  stratigraphy,  and  structure  should  be 
acquired  so  that  the  field  work  may  be  planned  to  proceed  from 
the  simple  and  evident  to  the  complex  and  obscure.  Such  a 
reconnaissance  should  always  precede  the  study  of  economic 
problems  and  should  generally  cover  a  much  larger  area  than  will 
subsequently  be  worked  in  detail.  The  geologist  should  seek 
an  early  opportunity  to  become  acquainted  with  the  best-informed 
and  most  representative  mining  men  of  the  district  under  exam- 
ination, since  much  valuable  information,  such  as  drill  records, 
mine  maps,  etc.,  obtainable  in  no  other  way,  can  often  be  pro- 
cured from  them.  To  secure  their  confidence  and  cooperation 
is  therefore  important. 

Work  of  assistants.  The  responsibility  for  both  quantity 
and  quality  of  work  accomplished  by  a  party  rests  with  the  chief. 
He  should  see  that  assistants  work  to  the  best  advantage,  and 
no  assistant  should  be  permitted  to  carry  on  independent  work 
until  his  reliability  and  capacity  have  been  thoroughly  tested. 
The  work  of  assistants  should  be  so  arranged  that  the  chief  will 
have  opportunity  to  check  their  results  at  frequent  intervals. 
This  inspection  should  be  actual,  and  not  merely  perfunctory, 
and  should  extend  to  notebooks,  maps,  specimen  labels,  etc.  It 


ESTIMATES  OF  DISTANCE,  ETC.        21 

is  highly  important,  both  for  the  chief  and  the  assistant,  that 
there  should  be  full  discussion  of  the  problems  under  investiga- 
tion during  the  progress  of  the  work. 


ESTIMATES    OF    DISTANCE,    ETC.  j 

It  is  not  always  practicable  or  necessary  to  make  actual  meas- 
urements of  distances,  dimensions,  or  angles.  In  many  cases  the 
measurements  cannot  be  made  by  reason  of  inaccessibility,  and 
in  others  the  degree  of  accuracy  required  is  not  such  as  to  justify 
the  expenditure  of  time  involved.  It  becomes  necessary  then 
to  substitute  estimates,  and  their  accuracy  depends  in  part  on 
natural  aptitude,  but  chiefly  on  training.  The  field  geologist 
should  therefore  train  his  eye  and  judgment  so  as  to  attain  the 
highest  possible  degree  of  accuracy.  It  is  well  to  form  the  habit 
of  making  estimates  before  measuring  distances  or  angles,  for 
comparison  with  results  of  the  measurement.  Only  by  so  verify- 
ing estimates  can  the  desired  degree  of  accuracy  be  attained. 

Large  distances  and  altitudes  can  be  estimated  best  by  apply- 
ing some  unit  of  measurement.  Thus  by  repeated  trials  a  hori- 
zontal distance  of  100  or  1000  feet  should  be  estimated  within  a 
small  percentage  of  error,  and  these  distances  may  be  used  as 
units  for  estimating  the  greater  distance.  In  the  same  way  6 
or  12  feet  of  altitude  is  easy  of  estimate  and  may  be  used  as  a 
measure  in  determining  the  height  of  a  cliff  or  steep  slope.  The 
45°  angle  can,  with  practice,  be  determined  almost  as  accurately 
with  the  eye  alone  as  with  an  ordinary  clinometer,  and  by  sub- 
division any  other  vertical  angle  can  be  obtained.  I 

HORIZONTAL    MEASUREMENTS 

The  necessity  for  determining  horizontal  distances  with  rea- 
sonable accuracy  is  of  constant  occurrence  and  a  variety  of 
methods  may  be  employed,  depending  on  the  conditions  present 
and  the  degree  of  accuracy  required.  These  methods,  named 
in  the  order  of  frequency  with  which  they  will  be  employed,  are 
(a)  pacing,  (6)  revolutions  of  a  wheel,  (c)  tape,  and  (d)  stadia. 


22  GENERAL    INSTRUCTIONS 

Pacing.  Every  field  geologist  should  be  able  to  measure  dis- 
tances by  pacing,  with  an  average  error  not  greater  than  2  per 
cent  on  level  ground  and  not  greater  than  10  per  cent  on  the 
roughest  ground  and  steep  slopes.  The  length  of  the  pace  should 
be  accurately  determined  under  a  variety  of  conditions.  The 
accuracy  is  increased  by  making  the  pacing  step  slightly  longer 
than  the  ordinary  walking  step.  The  separate  steps  may  be 
counted,  in  which  case  some  form  of  tally  register  should  be  used, 
or  preferably  only  each  fourth  step  should  be  counted,  giving  a 
four-step  unit.  This  is  conveniently  done  by  naming  a  digit  in 
the  thousands,  hundreds,  tens,  and  units  place  for  the  four  steps 
constituting  the  unit.  Thus  the  first  pace  will  be  0-0-0-1,  the 
second  0-0-0-2,  the  tenth  0-0-1-0,  etc.  After  a  little  practice 
the  count  becomes  subconscious  and  distracts  the  attention  only 
slightly  from  other  things. 

Distances  may  also  be  measured  with  a  fair  degree  of  accuracy, 
if  the  ground  is  not  too  rough,  by  counting  a  horse's  steps.  The 
length  of  the  pace  should  be  determined  for  each  animal  before 
it  is  used  as  a  unit  of  distance. 

Revolutions  of  a  wheel.  Where  measurements  are  to  be  made 
on  a  road  and  a  buggy  or  buckboard  is  available,  there  is  great 
economy  in  the  use  of  the  circumference  of  a  wheel  as  the  unit. 
The  actual  revolutions  may  be  counted,  a  piece  of  cloth  or  brush 
being  tied  to  one  of  the  spokes  as  a  marker,  or  an  odometer  may 
be  used.  These  instruments  are,  however,  generally  unreliable, 
and  may  introduce  large  errors  into  the  measurement.  If  an 
odometer  is  used  it  is  preferable  to  select  one  which  records  the 
actual  revolutions  of  the  wheel  rather  than  one  reading  directly 
to  miles  and  fractions  of  a  mile.  In  fact,  for  traverse  work  the 
latter  type  is  practically  useless,  as  the  smallest  fraction  to  which 
it  can  be  read  is  beyond  the  allowable  limit  of  error  in  such  work. 

In  making  a  traverse  with  wheel  measurements  the  scale  used 
for  plotting  on  the  plane  table  or  notebook  should  be  such  that 
an  even  number  of  revolutions  is  represented  by  a  unit  division 
of  the  inch,  so  that  it  will  not  be  necessary  to  reduce  the  revo- 
lutions to  feet  before  plotting. 

Tape  line.  The  field  outfit  should  always  contain  a  50  or 
100-foot  tape,  preferably  steel,  for  use  in  measuring  short  dis- 


ANGULAR    MEASUREMENTS  23 

tances  where  a  high  degree  of  accuracy  is  required.  It  is  espe- 
cially useful  in  measuring  sections  for  obtaining  thickness  where 
the  conditions  do  not  permit  the  use  of  a  wheel.  Two  men  are 
required  for  its  use  and  a  tally  register  is  desirable. 

Stadia.  Where  lines  are  to  be  run  without  reference  to  roads, 
so  that  a  wheel  cannot  be  used,  and  where  a  higher  degree  of 
accuracy  is  required  than  can  be  obtained  by  pacing,  the  stadia 
method  may  be  employed.  Any  instrument  carrying  a  telescope 
and  vertical  circle  may  be  used  for  this  purpose,  as  a  transit  or 
telescopic  alidade.  To  the  reticule  of  the  telescope  are  added 
two  or  more  fixed  horizontal  wires  placed  at  certain  distances 
apart.  A  rod  subdivided  to  suit  the  interval  between  the  wires 
and  painted  in  distinct  colors  forms  part  of  the  outfit.  When 
the  rod  is  set  up  at  a  distance  from  the  telescope,  that  distance 
is  ascertained  from  the  number  of  subdivisions  included  between 
the  wires  of  the  telescope,  the  value  of  each  division  of  the  rod 
being  known.  In  measuring  distance  on  slopes  correction  must 
be  made  to  reduce  the  reading  to  horizontal  distance. 

In  case  it  becomes  necessary  for  the  geologist  to  use  the  stadia, 
he  should  thoroughly  familiarize  himself  with  its  construction 
and  the  precautions  and  corrections  involved. 


ANGULAR    MEASUREMENTS 

In  all  regions  except  those  in  which  the  bedding  planes  are 
approximately  horizontal,  or  in  which  only  massive  crystalline 
rocks  occur,  determinations  of  strike  and  dip  must  be  made 
upon  practically  every  outcrop.  This  involves  the  measurement 
of  vertical  angles,  which  may  be  done  with  a  clinometer  (a  con- 
venient form  of  plumb  line),  or  with  spirit  level  and  vertical  circle 
(Abney  hand  level  or  Brunton  compass).  Less  frequently,  angu- 
lar measurements  are  required  for  the  determination  of  land 
slopes  or  heights  of  inaccessible  objects. 

In  determining  dip  angles  the  edge  of  the  clinometer  may  be 
placed  directly  upon  the  sloping  surface  to  be  determined,  but 
care  must  be  exercised  that  the  part  of  the  surface  selected 
actually  represents  the  average  slope  of  the  beds,  and  that  the 


24  GENERAL    INSTRUCTIONS 

measurement  of  the  angle  is  not  influenced  by  local  irregulari- 
ties. Also,  to  obtain  the  correct  dip  the  edge  of  the  clinometer 
must  be  placed  on  a  line  exactly  at  right  angles  to  the  strike — 
the  intersection  of  a  horizontal  plane  with  the  inclined  bedding 
plane  or  other  surface.  Where  the  exposure  is  such  as  to  permit 
it,  better  results  can  be  secured  by  sighting  to  the  edge  of  the  beds 
across  the  edge  of  the  clinometer  at  such  a  distance  that  beveral 
feet  will  be  covered  and  the  average  dip  obtained.  Care  must 
be  taken  to  have  the  eye  as  near  as  possible  in  the  extension  of 
the  plane  whose  inclination  is  being  measured,  and  to  sight  on 
a  horizontal  line. 

Land  slopes  may  be  measured  with  a  clinometer  when  they 
can  be  seen  in  profile,  but  elsewhere  by  means  of  a  vertical  circle, 
approximately  with  the  Abney  level  or  Brunton  compass,  and 
accurately  with  a  transit  or  telescopic  alidade. 


VERTICAL   MEASUREMENTS 

The  means  employed  for  determining  differences  in  elevation 
will  be  varied  according  to  the  conditions  and  degree  of  accuracy 
required.  The  instruments  most  used  are  (a)  the  aneroid,  (6)  the 
hand  level,  (c)  the  wye  level,  and  (d)  the  telescope  with  vertical 
circle. 

Aneroid.  The  ease  with  which  the  aneroid  is  carried  and  read 
makes  it  an  exceedingly  useful  instrument  in  geologic  field  work. 
The  limitations  to  which  it  is  subject  should,  however,  always 
be  kept  in  mind.  Since  the  determination  of  difference  in  ele- 
vation depends  on  differences  of  atmospheric  pressure,  the  apparent 
difference  between  two  points  may  be  increased  or  decreased  by 
changes  in  the  general  barometric  pressure  of  the  region  taking 
place  during  the  interval  between  the  taking  of  the  observations. 
The  time  interval  between  readings  should  therefore  be  as  short 
as  practicable.  The  aneroid  should  be  used  differentially  only, 
and  its  readings  should  be  checked  by  reference  to  known  eleva- 
tions whenever  opportunity  is  afforded  during  the  day  as  well 
as  at  the  beginning  and  end  of  each  day's  work.  Whenever 
checked  by  comparison  with  a  known  elevation  the  movable 


VERTICAL   MEASUREMENTS  25 

circular  scale  should  be  turned  so  that  the  needle  is  opposite  the 
correct  point  on  the  scale.  The  elevations  should  then  be  read 
direct  from  the  scale  in  feet.  If  no  check  can  be  made  for  several 
hours,  and  if,  when  checked,  the  reading  is  found  to  be  too  high 
or  low  by  more  than  a  contour  interval,  the  error  may  be  dis- 
tributed backward  over  the  readings  in  proportion  to  the  intervals 
of  time  between  them,  or,  in  case  of  a  traverse,  in  proportion  to 
the  distance. 

The  uncertainty  of  the  aneroid  is  greatly  increased  in  unsettled 
weather,  when  barometric  changes  are  rapid,  and  it  is  practically 
useless  immediately  before  and  after  a  thunderstorm. 

On  account  of  the  delicate  mechanism  employed  to  magnify 
the  slight  expansion  and  contraction  of  the  vacuum  box  and 
transmit  it  to  the  index  needle  aneroids  are  easily  injured  and 
must  be  protected  from  any  sudden  jar.  They  should  be  carried 
preferably  in  a  closely  fitting  vest  or  shirt  pocket,  secured  by 
a  string,  or  in  a  case  fastened  by  a  close  loop  to  the  belt.  They 
should  never  be  carried  by  a  strap  over  the  shoulder — particularly 
on  horseback — or  loose  in  the  coat  pocket  or  collecting  bag. 

Hand  level.  Small  differences  of  elevation  which  must  be 
determined  with  considerable  accuracy,  as  for  obtaining  thick- 
ness of  beds,  should  generally  be  measured  with  some  form  of 
hand  level.  The  Locke  level  is  simplest  in  construction  and  most 
convenient  to  carry,  and  will  serve  ordinary  purposes.  The 
Abney  level  is  likewise  serviceable  and  may  be  used  also  to 
measure  vertical  angles.  The  Brunton  compass  may  be  used 
as  a  hand  level,  and  if  so  used  it  will  be  unnecessary  to  carry  a 
level  in  addition.  In  case  a  large  amount  of  hand  leveling  is  to 
be  done,  and  the  slopes  are  gentle,  as  on  roads,  the  telescopic 
hand  level  is  the  best  instrument  to  use. 

The  distance  to  the  observer's  eye  above  the  ground  should  be 
determined  to  the  nearest  tenth  of  a  foot.  The  best  results  are 
obtained  on  a  moderately  steep  slope,  so  that  the  point  deter- 
mined on  a  level  with  the  eye  may  hot  be  too  distant  for  easy 
identification  when  it  is  reached.  On  a  very  steep  slope  eleva- 
tions may  be  determined  with  a  fair  degree  of  accuracy  without 
an  instrument,  by  estimating  the  horizontal  point  with  the  eye. 

It   sometimes   becomes   necessary   to   determine   differences   in 


26  GENERAL    INSTRUCTIONS 

elevation  where  the  ordinary  method  of  using  the  hand  level 
by  sighting  to  the  ground  ahead  is  not  applicable,  as  where  the 
slope  is  gentle  and  covered  with  tall  grass  or  brush  so  that  the 
ground  cannot  be  seen.  Under  such  circumstances  the  assistance 
of  a  rodman  is  necessary.  If  sights  of  200  feet  or  more  are  to  be 
taken  the  hand  level  may  be  fastened  across  the  end  of  a  stick 
of  convenient  length — about  5  feet — and  so  held  much  steadier 
than  without  such  a  support.  The  Abney  level  is  supplied  with 
a  socket  for  use  with  a  JacobstafT.  A  level  rod  may  be  made 
from  a  light,  straight  pole,  10  feet  long,  the  end  of  a  rule  held 
against  it  being  used  as  a  target.  Fore  sights  and  back  sights 
are  made  and  recorded  as  when  using  the  wye  level,  but  the  height 
of  the  instrument  is  constant. 

Wye  level.  It  sometimes  becomes  necessary  to  determine 
elevations  more  accurately  than  can  be  done  by  the  methods 
described  above.  This  is  the  case,  for  example,  where  the  minor 
structures  are  being  worked  out  in  an  oil  field  and  the  elevation 
of  outcrops  or  of  well  heads  must  be  known  within  a  foot  or  two. 
Under  such  conditions  flying  levels  are  run  with  a  wye  level  from 
the  nearest  bench  mark.  This  work  is  slow  and  expensive  and 
should  therefore  be  confined  to  the  absolutely  necessary  locations 
and  used  only  where  there  is  a  good  topographic  base  available. 
A  special  notebook  adapted  for  both  level  and  geologic  notes  has 
been  designed  by  M.  J.  Munn,  and  should  be  used  where  much 
of  this  work  is  done. 

Telescope  with  vertical  circle.  In  case  the  stadia  method 
is  employed  for  measuring  distances,  either  with  a  transit  or 
with  a  telescopic  alidade,  elevations  will  at  the  same  time  be 
obtained  by  means  of  vertical  angles.  Tables  for  obtaining  ele- 
vations from  stadia  readings  are  given  in  "  Geographic  Tables 
and  Formulas,"  published  by  the  U.  S.  Geological  Survey.  The 
use  of  this  instrument  in  geologic  work,  however,  will  be  excep- 
tional, and  before  attempting  to  use  it  the  geologist  should  acquire 
experience  under  a  competent  instructor. 


DETERMINATION    OF    THICKNESS    OF    BEDS       27 


DETERMINATION    OF    THICKNESS    OF  BEDS 

In  the  study  of  areal,  stratigraphies,  and  structural  geology, 
the  thickness  of  beds  must  be  determined  at  many  points.  The 
character  of  the  topography  and  of  the  outcrops,  and  inclination 
of  the  beds,  will  determine  the  method  employed. 

The  simplest  case  is  where  the  beds  are  approximately  hori- 
zontal and  the  slopes  are  steep.  Under  such  conditions  it  is 
necessary  only  to  measure  the  vertical  distances  between  upper 
and  lower  limits  of  the  stratigraphic  units  by  aneroid,  hand 
level,  or  wye  level,  depending  on  the  degree  of  accuracy  required. 
If  the  slope  on  which  the  section  is  made  is  very  steep — 30°  or 
more — dips  of  3°  or  less  may  be  neglected. 

If  the  beds  dip,  three  factors  must  be  determined — (a)  dip 
angle,  (fr)  slope  angle,  and  (c)  distance  across  the  beds  normal 
to  the  strike;  and  three  cases  occur — (a)  with  surface  horizon- 
tal, (6)  with  surface  sloping  and  beds  dipping  into  the  slope,  and 
(c)  with  surface  sloping  and  beds  dipping  with  the  slope.  These 
three  cases  are  shown  in  Fig.  4,  from  which  it  is  seen  that — 


FIG.  4.  —  Diagram  illustrating  determination  of  thickness  of  beds  by  trigono- 
metric method. 


(a)  Thickness  of  beds  A  to  £  = 

(b)  Thickness  of  beds  B  to  C  =  6 

(c)  Thickness  of  beds  C  to  D  =  c 


BAa. 

=  J5CXsin  (CBe  +  eBb). 
=  CDXs'm  (fCc-fCD). 


The  dip  angle  (BAa  =  eBb=fCc)  is  measured  directly  with  the 
clinometer;   the  slope  angles  (CBe  and  /CD)  are  either  measured 


28  GENERAL    INSTRUCTIONS 

directly  or  obtained  from  the  difference  in  elevation,   which  is 
the  slope  distance  into  the  sine  of  the  slope  angle,  i.e., 


These  results  may  be  expressed  in  the  following  rules: 

(1)  Where  the  surface  is  horizontal,  the  thickness  equals  the 
distance  across  the  dipping  beds  multiplied  by  the  sine  of  the 
dip  angle.  (2)  Where  the  surface  slopes  and  beds  dip  into  the 
slope  the  thickness  equals  the  distance  across  the  beds  multiplied 
by  the  sine  of  the  sum  of  dip  and  slope  angles.  (3)  Where  the 
surface  slopes  and  beds  dip  with  the  slope  the  thickness  equals 
the  distance  across  the  beds  multiplied  by  the  sine  of  the  dif- 
ference of  dip  and  slope  angles. 

To  facilitate  calculations  a  table  of  natural  sines  and  tangents 
is  given  on  page  *3T.  ^ 

With  increasing  dip  the  horizontal  measurement  becomes  rela- 
tively more  important  than  the  vertical,  and  where  the  dip  becomes 
approximately  90°  the  difference  in  elevation  between  limits  of 
the  beds  may  be  neglected  and  the  true  thickness  will  be  repre- 
sented by  the  horizontal  distance  measured  at  right  angles  to  the 
strike  of  the  beds. 

A  convenient  method  of  determining  the  thickness  of  beds, 
without  calculation,  when  the  angle  of  dip  and  horizontal  distance 
across  the  outcrop  normal  to  the  strike  are  known,  is  by  the  use 
of  the  diagram  shown  in  Fig.  5.  The  horizontal  rulings  corre- 
spond to  degrees.  Any  convenient  scale  may  be  adopted  for 
the  spaces  between  vertical  rulings,  as  1,  10,  50,  or  100  feet.  To 
determine  the  thickness  of  beds,  find  the  horizontal  line  corre- 
sponding to  the  dip  angle  and  follow  it  to  the  right  for  a  distance 
corresponding  to  the  measured  distance  across  the  outcrop  on  the 
scale  selected.  If  this  distance  coincides  with  a  curved  line  the 
latter  is  followed  to  the  top  of  the  diagram,  where  the  thickness 
is  determined  directly  by  the  distance  between  it  and  the  left 
margin,  the  same  scale  being  used.  If  the  point  falls  between 


DETERMINATION    OF    THICKNESS    OF    BEDS       29 

two  curved  lines,  the  measurement  is  made  to  a  point  at  the  top 
of  the  diagram  having  the  same  relation  to  these  lines. 

A  convenient  method  for  the  direct  measurement  of  thickness 


FIG.  5. — Diagram  for  use  in  determination  of  thickness  of  beds  by  graphic 
method. 

in  making  detailed  sections,  particularly  on  steep  slopes  or  with 
steeply  dipping  beds  and  where  exposures  are  nearly  continuous, 
is  as  follows.  To  the  upper  end  of  a  rod  of  convenient  length — 
5  feet  is  about  right  for  a  man  of  ordinary  height — is  fastened 


30  GENERAL   INSTRUCTIONS 

a  short  arm  to  form  a  right-angled  T.  A  zigzag  jointed  5-foot  rule 
may  be  used  instead  of  the  rod.  In  addition  to  the  rod  either 
(a)  a  hinged  clinometer  with  level  on  one  arm,  or  (b)  an  Abney 
level,  or  (c)  a  Brunton  compass  is  used.  The  dip  of  the  beds  is 
determined,  and  if  a  clinometer  is  used  the  arms  are  opened  so 
that  the  angle  between  them  is  equal  to  the  dip  angle.  If  then, 
the  lower  limb  of  the  clinometer  is  held  firmly  on  the  top  of  the 
T  rod  and  the  rod  is  inclined  until  the  upper  limb  is  horizontal, 
the  lower  limb  will  be  in  the  plane  of  bedding  projected  upward 
toward  the  observer.  By  sighting  down  this  limb  the  bed  in 
whose  plane  it  lies  is  determined  and  the  beds  between  this  plane 
and  the  foot  of  the  rod  have  a  thickness  equal  to  its  length.  The 
foot  of  the  rod  is  now  moved  up  to  this  bed  and  again  brought 
into  position  so  that  the  upper  limb  of  the  clinometer  is  horizon- 
tal and  the  rod  is  at  right  angles  to  the  bedding,  and  a  new  point 
is  obtained  by  sighting  down  the  lower  limb.  Count  is  kept  of 
the  unit  thicknesses  and  the  total  thickness  between  determined 
limits  is  obtained  with  no  calculation  except  a  multiplication  of 
the  length  of  the  rod  into  the  number  of  sights  taken.  The 
method  is  very  similar  to  the  use  of  the  hand  level  for  obtaining 
elevations,  and  becomes  identical  with  it  when  the  dip  becomes 
zero. 

When  the  Abney  level  or  the  Brunton  compass  is  used  the 
method  is  the  sa*ne,  except  that  the  vernier  arm  carrying  the 
level  is  set  at  a  point  on  the  divided  circle  corresponding  to  the 
dip  angle. 

Where  surface  exposures  are  nearly  or  quite  continuous,  so 
that  it  is  not  necessary  to  follow  stream  channels,  and  where 
dips  are  steep  and  variable,  sections  should  be  measured  as  nearly 
as  possible  at  right  angles  to  the  strike.  In  order  to  get  the 
best  exposures  it  is  generally  necessary  to  make  occasional  offsets 
along  the  strike,  following  some  easily  identifiable  bed  or  contact. 
Measurements  along  the  strike  need  not  be  made  with  the  same 
degree  of  accuracy  as  those  normal  to  the  strike.  The  notes 
of  such  a  traverse  may  conveniently  be  kept  in  tabular  form, 
a  page  of  the  notebook  being  ruled  into  columns  for  (1)  number 
of  the  station,  (2)  character  of  rocks,  (3)  distance  (measured 
on  the  slope),  (4)  slope  angle  (U  when  the  slope  is  up  in  the  direc- 


DETERMINATION    OF    THICKNESS  OF    BEDS       31 

tion  of  traverse  and  D  when  it  is  down),  (5)  altitude  (or  elevation 
with  reference  to  any  assumed  datum),  (6)  dip  angle  (F  when 
the  dip  is  in  the  direction  of  the  traverse,  and  B  when  the  reverse), 
(7)  strike,  and  (8)  thickness.  All  columns  except  the  last  should 
be  filled  as  the  traverse  proceeds,  and  where  direct  measure- 
ments can  be  made  the  thickness  should  be  recorded  also.  Col- 
umns 3  to  6  contain  the  necessary  data  for  computing  thick- 
nesses by  the  methods  given  above,  if  they  cannot  be  measured 
directly. 

In  case  it  is  necessary  to  make  surface  measurements  diagon- 
ally across  the  strike,  the  distance  normal  to  the  strike  is  deter- 
mined by  the  solution  of  a  right-angled  triangle,  the  line  traversed 
being  the  hypothenuse  (h)  and  the  angle  which  this  line  makes 
with  the  strike  being  an  adjacent  angle  (c).  The  side  (B)  opposite 
this  known  angle  will  be  the  distance  on  the  slope  normal  to  the 
strike — that  is, 

B-J-. 

,  sin  c 

In  making  sections  of  steeply  inclined  and  poorly  exposed 
beds,  the  observed  dips  at  the  nearest  exposures  often  show 
wide  variation.  A  convenient  method  of  obtaining  approxi- 
mate thicknesses  under  such  conditions  is  as  follows:  Measure 
horizontal  distances  as  nearly  as  possible  at  right  angles  to  the 
strike,  locating  and  measuring  as  many  dips  as  possible.  Con- 
struct a  normal  profile  to  scale  and  plot  upon  it  all  dips  pro- 
jected in  their  proper  horizontal  relations,  as  in  Fig.  6.  Extend 
the  dips  in  straight  lines  above  and  below  the  profile.  At  the 
intersection  of  each  dip  line  with  the  surface  profile  draw  a  line 
at  right  angles  and  extend  it  until  it  intersects  the  dip  lines  on 
either  side.  The  thickness  of  the  beds  between  any  two  observed 
exposures,  as  A  and  B,  will  be  equal  to  one-half  the  sum  of  the 
lines  intersected  between  the  dip  lines  above  and  below  the 
profile — that  is, 

Ab'+aB 
Thickness  of  beds  A  to  £= . 

Cd'+cD 
Thickness  of  beds  C  to  D  = ,  etc. 


32  GENERAL    INSTRUCTIONS 

These  values  can  be  scaled  off  directly  from  the  diagram.  The 
construction  is  based  on  the  assumption  that  the  dip  varies 
uniformly  from  A  to  B,  C  to  D,  etc.,  which  may  or  may  not  be 
the  case.  Moreover,  the  results  are  too  large  if  the  observed 
rdips  are  at  different  elevations  and  converge  downward,  and 
they  are  too  small  if  they  diverge.  Thus  in  the  section  repre- 
sented by  Fig.  3  the  thicknesses  will  be  approximately  correct 
from  A  to  E,  too  small  from  E  to  Ft  and  too  large  from  F  to  G. 
The  method  is  applicable  therefore  only  where  the  profile  is 


FIQ.  6. — Diagram  illustrating  determination  of  thickness  of  Jaeds  by  construc- 
tion method. 

approximately  horizontal   and   should   be   employed   only  where 
the  exposures  are  not  sufficient  for  more  accurate  measurement. 


DETERMINATION    OF    DEPTH    OF    BEDS 

It  is  frequently  necessary  to  determine  in  the  field  the  depth 
of  a  particular  bed  or  horizon  at  a  distance  from  its  outcrop, 
or  to  determine  the  distance  from  the  outcrop  at  which  a  coal 
bed  or  oil  sand  reaches  a  given  depth.  The  problem  may  be 
solved  by  graphic  or  trigonometric  methods. 

The  graphic  method  involves  the  construction  of  a  section 
at  right  angles  to  the  strike.  Dips  are  plotted  on  the  profile 
drawn  to  scale  and  showing  the  thicknesses  of  intervening  beds 
as  determined  by  the  methods  given  in  paragraphs  1  to  8,  above. 
The  depth  of  a  bed  at  any  point,  or  the  distance  from  the  out- 
crop at  which  any  bed  reaches  a  given  depth,  can  then  be  sealed 
off  directly  from  the  section. 


DETERMINATION    OF    DEPTH    OF    BEDS 


33 


By  the  trigonometric  method  three  cases  occur — (1)  where 
the  surface  below  which  the  depth  is  to  be  determined  is  hori- 
zontal, (2)  where  the  surface  slopes  and  the  beds  dip  into  the 
slope,  and  (3)  where  the  surface  slopes  and  the  beds  dip  with 
the  slope.  The  three  cases  are  shown  in  Fig.  7,  from  which  it 
is  seen  that — 


FIG,  7. — Diagram  illustrating  determination  of  depth  of  beds  by  trigonometric 

method. 


BAa. 

BCXsm  CBb 
cos  eBb 

CDXs'mDCc 

cos  fCc     ' 


(1)  Depth  of  bed  Aa  at  B  =  Ba  = 

(2)  Depth  of  bed  Bb  at  C  =  Cb  = 

(3)  Depth  of  bed  Cc  at  D=Dc  = 
and  depth  of  bed  Aa"  at  D  =  Da"  -- 


In  this  figure  A  B,  BC,  and  CD  are  the  surface  distances  nor- 
mal to  the  strike  of  the  beds;  BAa,  eBb,  and  fCc  are  the  dip 
angles;  CBb  is  the  sum,  and  DCc  is  the  difference  of  dip  and 
slope  angles. 

For  convenience  in  determinations  where  the  surface  is  approxi- 
mately horizontal,  a  table  giving  depths  of  a  bed  for  various 
angles  of  dip  and  distances  from  outcrop  is  inserted  on  page 
Where  the  slope  is  gentle  and  great  accuracy  is  not  required, 


34  GENERAL    INSTRUCTIONS 

this  table  may  be  used,  by  adding  to  the  depths  given  the  dif- 
ference in  elevation  between  the  outcrop  and  the  point  at  which 
the  depth  is  desired — the  difference  in  elevation  being  positive 
when  this  point  is  higher  than  the  outcrop  and  negative  when 
it  is  lower.  The  errors  will  generally  be  well  within  the  limits 
of  accuracy  of  measurement,  and  the  formulas  given  above  need 
not  be  employed  except  with  steep  slopes. 


DETERMINATION    OF    FAULTS 

Where  exposures  are  sufficiently  abundant  the  facts  necessary 
for  the  determination  of  the  direction  and  extent  of  a  displace- 
ment, particularly  if  it  is  relatively  small  in  amount,  may  be 
observed  directly.  As  a  rule,  however,  the  dip  of  the  fault  plane 
and  the  direction  and  amount  of  displacement  must  be  inferred 
from  a  number  of  observations  at  different  localities.  Field 
observations  should  be  made  with  especial  care  and  complete- 
ness in  the  vicinity  of  faults,  for  it  is  here  that  the  unexpected 
is  always  apt  to  occur. 

Dip  of  fault  plane.  It  often  happens  that  the  contact  of 
rocks  on  opposite  sides  of  a  fault  plane  cannot  be  seen  at  any 
point,  although  the  fault  may  be  traced  for  many  miles.  To 
afford  data  for  determination  of  the  dip,  as  many  points  as 
possible  on  the  fault  should  be  accurately  located  both  horizon- 
tally and  vertically.  The  points  should  be  selected  so  that  the 
horizontal  distances  will  be  as  small,  and  the  vertical  as  large, 
as  possible.  Three  points  properly  selected  and  accurately  located 
will  give  better  results  than  a  larger  number  less  carefully  chosen 
and  determined.  The  best  locations  are  at  the  bottom  of  a  valley 
transverse  to  the  fault  and  on  the  hills  on  either  side.  The  three 
points  fix  the  position  of  the  fault  plane,  and  its  dip  or  the  angle 
it  makes  with  the  horizontal  may  be  determined  by  construction 
or  trigonometric  methods.  The  trigonometric  method  involves 
the  solution  of  a  number  of  triangles  and  the  extraction  of  square 
roots.  Its  practical  application,  therefore,  necessitates  the  use 
of  logarithmic  tables,  which  are  not  generally  accessible  in  the 
field.  The  method  by  construction  is  relatively  simple  and 


DETERMINATION    OF   FAULTS 


35 


requires  only  a  protractor,  dividers,  and  scale.     This  method  is 
illustrated  in  Fig.  8,  and  is  as  follows: 

Let  the  three  points  in  the  fault  plane  be  A,  B,  and  C.  Let 
C  be  the  lowest  and  B  the  highest,  the  differences  in  elevation 
having  been  determined.  The  horizontal  or  slope  distances 
from  C  to  A  and  B,  and  the  azimuth  of  the  lines  connecting 
them,  have  also  been  determined.  Lay  off  with  the  protractor 
the  lines  CA  and  CB,  in  proper  azimuth  on  the  scale  adopted. 
If  these  lines  represent  slope  distances,  project  the  points  A  and 
B  upon  the  horizontal  plane  passing  through  C,  as  follows: 


FIG.  8. — Diagram  illustrating  determination  of  dip  of  fault  plane. 


Construct  a  right  triangle  (BCb')  with  CB  as  the  hypothenuse 
and  the  difference  in  elevation  between  C  and  B  as  the  perpen- 
dicular. Lay  off  on  CB  a  distance  equal  to  the  base  of  this  right 
triangle — that  is,  Cb  =  Cbf.  Determine  the  point  a  on  CA  in 
like  manner.  Draw  a  line  through  a  and  b  and  extend  it  beyond 
a.  The  triangle  aCb  is  the  horizontal  projection  of  the  portion 
of  the  inclined  plane  included  by  the  lines  connecting  A,  5, 
and  C.  If  the  distances  between  C  and  A  and  B  are  horizontal 
distances  this  projection  is  not  necessary,  since  the  triangle  can 
be  drawn  at  once — in  the  horizontal  plane — and  the  line  com- 
pleting the  triangle  will  be  drawn  through  A  and  B. 


36  GENERAL    INSTRUCTIONS 

At  a  and  b  erect  perpendiculars  equal  respectively  to  A  a'  and 
Bb'j  and  draw  a  line  through  their  extremities  to  its  intersec- 
tion with  the  line  ba  extended  at  O.  This  point  of  intersection 
will  be  in  the  horizontal  plane  and  also  in  the  inclined  plane. 
'Since  C  also  is  in  the  same  horizontal  plane  and  in  the  inclined 
plane,  a  line  connecting  0  and  C  will  be  the  intersection  of  these 
two  planes,  and  hence  the  strike  line.  From  the  horizontal  pro- 
jection of  either  of  the  points,  as  b,  let  fall  a  perpendicular  to  D 
on  this  strike  line  OC  extended.  From  b  draw  bd  perpendicular 
to  bD  and  equal  to  Bb',  the  difference  in  elevation  between  C 
and  B.  Connect  its  extremity  with  D  and  the  angle  bDd  will 
be  the  angle  sought,  the  inclination  of  the  fault  plane  to  the 
horizontal. 

Unless  the  field  measurements  have  been  made  with  excep- 
tional accuracy  the  error  in  the  above  solution  will  come  well 
within  the  limit  of  error  of  observation. 

This  method  is  of  course  applicable  in  the  determination  of 
strike  and  dip  of  any  inclined  plane  in  which  the  relative  posi- 
tion of  three  points  is  known.  Thus  it  will  be  found  useful  in 
determining  the  strike  and  dip  of  a  bed  which  is  intersected  by 
drill  holes,  or  which,  from  the  nature  of  its  exposures,  does  not 
admit  of  direct  measurement. 

Angle  of  intersection  with  oblique  vertical  plane.  It 
frequently  becomes  necessary  to  determine  the  angle  of  inter- 
section of  a  fault  (or  other  inclined  plane)  with  a  vertical  plane 
oblique  to  the  strike  of  the  fault. 

The  trigonometric  solution  may  be  used  when  tables  of  natural 
or  logarithmic  functions  are  at  hand.  Let  m  be  the  angle  of 
dip  of  the  inclined  plane  and  n  the  angle  between  the  strike  of 
the  inclined  plane  and  the  vertical  plane.  To  find  x,  the  angle 
which  the  line  of  intersection  of  the  two  planes  makes  with  the 
horizontal, 

tan  #=tan  m  sin  n. 

The  problem  may  be  solved  by  construction  as  follows:  Let 
AK,  Fig.  9,  be  the  azimuth  of  the  vertical  plane;  draw  AL  so 
that  the  angle  KAL  =  n=ihe  angle  made  by  the  strike  of  the 
inclined  plane  and  the  azimuth  of  the  vertical  plane.  Take  any 


DETERMINATION   OF   FAULTS 


37 


point  (C)  on  AL  and  erect  a  perpendicular  CB.  With  CB  as 
a  base  construct  a  right  triangle  with  the  angle  BCD  =  m  =  ihe 
angle  of  dip  of  the  inclined  plane.  Draw  BD'  =  BD  and  at  right 
angles  to  A B.  Connect  A  and  D'.  The  angle  BAD'  =  x  will 
be  the  angle  sought. 


FIG.  9. — Diagram  illustrating  determination  of  angle  of  intersection  of  fault 
plane  with  vertical  plane  oblique  to  strike  of  fault. 

Percent  and  angular  inclination.  The  attitude  of  slightly 
inclined  bedding  planes  or  other  surfaces  is  generally  expressed 
by  engineers  in  percentages,  and  it  is  therefore  frequently  neces- 

TABLE  1. — CONVERSION  OF  PERCENT  GRADE  TO  ANGULAR  INCLINATION 


Percent 
Grade. 

Angular 
Inclination. 

Percent 
Grade. 

Angular 
Inclination. 

Percent 
Grade. 

Angular 
Inclination. 

1. 

35' 

7.00 

4° 

13.00 

7°  25' 

1.50 

52' 

7.50 

4°  15' 

14.00 

8° 

1.75 

1° 

8.00 

4°  35' 

15.00 

8°  30' 

2.00 

1°  10' 

8.50 

4°  50' 

15.85 

9° 

2.50 

1°  25' 

8.75 

5° 

16.00 

9°    5' 

3.00 

1°  45' 

9.00 

5°  10' 

17.00 

9°  40' 

3.50 

2° 

9.50 

5°  25' 

17.65 

10° 

4.00 

2°  15' 

10.00 

5°  45' 

18.00 

10°  15' 

4.50 

2°  35' 

10.50 

6° 

19.00 

10°  45' 

5.00 

2°  50' 

11.00 

6°  15' 

19.45 

11° 

5.25 

3° 

11.50 

6°  35' 

20.00 

11°  20' 

5.50 

3°  10' 

12.00 

6°  50' 

21.00 

11°  50' 

6.00 

3°  25' 

12.25 

7° 

21.25 

12° 

6.50 

3°  45' 

12.50 

7°  10' 

38  GENERAL    INSTRUCTIONS 

sary  to  convert  such  percentages  into  their  equivalent  angles. 
It  is  also  at  times  desired  to  convert  angular  inclination  into  the 
equivalent  percentage.  This  conversion  involves  the  use  of  a 
table  of  natural  tangents  more  extended  than  that  given  on 
page  42,  and  the  above  table  of  equivalents  is  therefore 
inserted.  The  angles  are  given  only  to  the  nearest  five  minutes, 
which  is  sufficient  for  geologic  purposes,  and  is  nearer  than  the 
angles  can  be  plotted  with  an  ordinary  protractor. 

Form  of  outcrop.  The  line  drawn  on  the  map  to  represent 
a  formation  boundary  is  the  trace  of  two  intersecting  surfaces — 
the  land  surface  and  the  surface  separating  the  overlying  and 
underlying  formations.  Since  both  are  irregularly  warped  sur- 
faces their  intersection  will  be  a  complicated  trace,  and  unless 
careful  consideration  is  given  to  the  geometric  relations  involved, 
the  location  of  the  line  is  apt  to  be  inconsistent  with  the  geologic 
structure.  If  it  were  possible  or  practicable  to  actually  trace 
on  the  ground  all  lines  which  will  be  shown  on  the  map,  their 
location  would  be  a  simple  matter,  but  the  nature  of  exposures 
generally  prevents  such  continuous  tracing,  and  even  where 
this  is  not  the  case  the  expenditure  involved  would  be  excessive 
and  prohibitory.  In  practice,  therefore,  the  location  is  deter- 
mined of  as  many  points  as  possible  under  the  limitations  of 
time  and  expense,  and  the  line  is  drawn  upon  the  map  between 
these  determined  points  so  as  to  be  consistent  with  the  form 
of  the  two  intersecting  surfaces. 

It  is  assumed  that  the  land  surface  will  be  accurately  repre- 
sented by  contours;  the  form  of  a  line  marking  the  intersection 
of  a  land  surface  so  represented  and  any  geological  surface,  as 
a  bedding  plane,  fault  plane,  unconformity,  eruptive  contact,  etc., 
may  be  considered  under  three  cases:  (1)  in  which  the  geologic 
plane  is  approximately  horizontal;  (2)  in  which  it  is  approxi- 
mately vertical,'  and  (3)  in  which  its  inclination  varies  anywhere 
between  0°  and  90°. 

(1)  It  is  evident  that  the  intersection  of  a  horizontal  geologic 
plane  with  any  land  surface  will  coincide  with  an  interpolated 
land  surface  contour,  since  by  definition  contours  are  simply 
the  traces  of  intersections  of  the  land  surface  with  equidistant 
imaginary  horizontal  planes. 


FORM   OF   OUTCROP  39 

A  boundary  between  horizontal  formations  will  therefore  be 
drawn  between  located  points  in  such  a  manner  as  not  to  cross 
a  contour  line.  The  drawing  of  such  lines,  particularly  if  a  large 
number  of  points  are  located,  is  a  rigid  check  on  the  accuracy 
of  the  contouring  and  will  generally  necessitate  more  or  less 
revision  of  the  latter. 

(2)  It  is  equally  evident  that  the   intersection   of  a  vertical 
geologic  plane  with  a  land  surface  is  not  influenced  by  the  inequali- 
ties of  the  latter,  and  therefore  has  no  definite  relation  to  the 
surface    contours.     Hence   a    boundary   between    vertical   forma- 
tions will  be  drawn  between  located  points  by  straight  lines  or 
confluent  curves,  regardless  of  contours. 

(3)  Between  the  two   extremes,   horizontal  and  vertical  dips, 
an   infinite   variety  of   relations   occur   between   the   intersection 
and  the  contour  lines.     Two  general  cases  may  be  discriminated; 
(a)  where  the  geologic  plane  dips  into  a  sloping  land  surface, 
and  (6)  where  it  dips  with  the  land  surface.     The  two  cases  are 
illustrated  by  the  formation  boundaries,  (a)  on  the  face,  and  (b) 
on  the  back  of  a  monoclinal  ridge,  as  shown  in  Fig.  10,  in  which 
the  contour  interval  is  100  feet  and  the  distance  from  A  to  B 
is  one  mile. 

Let  it  be  assumed  that  a  section  has  been  made  across  the  ridge 
from  AtoB  and  the  points  M,  N,  0,  and  P  on  the  formation  bound- 
aries accurately  located;  also  that  the  strike  and  dip  of  the  beds 
have  been  determined.  The  problem  is  to  determine  the  loca- 
tion of  the  boundaries  on  the  map  with  reference  to  the  con- 
tours when  continued  on  either  side  of  the  section. 

Points  on  these  lines  may  be  determined  in  the  following  man- 
ner. Construct  the  profile  AB  to  scale.  The  distance  between 
the  horizontal  ruled  lines  is  equal  to  the  contour  interval,  100 
feet,  and  the  profile  is  constructed  by  projecting  the  points  of  in- 
tersection of  the  profile  AB  and  the  various  contours.  Project  upon 
this  profile  the  points  M.  N,  0,  and  P,  and  draw  the  lines  M'm', 
N'n',  etc.,  the  angles  corresponding  to  the  determined  dip  of 
the  beds.  In  the  same  manner  construct  the  profiles  A'B',  and 
A"B".  The  point  ra',  at  which  the  dip  line  M'm'  intersects 
the  profile  A'B'  is  projected  upon  the  section  line  A'B',  and 
fixes  the  point  on  the  map  at  which  the  boundary  crosses  the  bot- 


40 


GENERAL   INSTRUCTIONS 


torn  of  the  ravine.     Between  M'  and  ra'  the  dip  line  crosses  the 
horizontal    ruled    line    corresponding   to    the    700-foot   contour. 


FIG.  10. — Diagram  illustrating  form  of  outcrop. 

This  point  projected  upon  the  map  gives  the  several  points  at 
which  the  boundary  mm  crosses  this  contour,  and  in  a  similar 
manner  the  points  at  which  it  crosses  the  600  and  500  contours 


FORM   OF    OUTCROP  41 

are  obtained.  Connecting  the  points  thus  located  on  the  map 
the  correct  position  of  the  boundary  is  fixed. 

The  dip  line  N'n'  does  not  cross  a  horizontal  line  between  N' 
and  n',  hence  the  boundary  nn  remains  between  the  900  and 
1000-foot  contours  in  crossing  the  ravine  A'B' '. 

In  the  same  way  points  are  located  on  oo  and  pp.  The  dip 
line  O'or  crosses  the  two  horizontal  lines  between  0'  and  o',  hence 
the  boundary  crosses  two  contours  between  the  point  0  and  the 
bottom  of  the  ravine  in  which  the  section  A'B'  is  located.  The 
points  at  which  it  crosses  the  contours  are  determined  as  above, 
by  projecting  the  intersections  of  the  dip  line  and  the  horizontal 
ruled  lines  upon  the  corresponding  contours. 

From  an  inspection  of  the  diagram  it  will  be  observed  (1)  that 
wherever  the  boundary  lines  cross  surface  depressions  they  bend 
in  the  direction  of  the  dip,  (2)  that  where  the  bedding  planes 
dip  into  the  slope  (mm  and  nn,  case  (a)  above),  the  boundary 
lines  bend  in  the  same  direction  as  the  contours,  but  less  acutely; 
(3)  that  where  the  bedding  planes  dip  with  the  slope  (oo  and  pp, 
case  (6)  above),  the  boundary  lines  bend  in  the  opposite  direc- 
tion from  the  contours,  and  the  deviation  from  a  straight  line 
increases  as  the  dip  decreases,  (4)  that  the  width  of  outcrop  of 
a  formation  which  occurs  on  a  slope  is  less  than  the  outcrop  of 
the  same  formation  on  a  level  surface  if  the  beds  dip  into  the 
slope,  and  greater  if  they  dip  with  the  slope. 


42 


GENERAL    INSTRUCTIONS 
TABLES   AND   FORMULAS 


L    £            COTANGENT                     -. 

TABLE 

2.     NA- 

TORAL  CIRCULAR 

TIONS. 

ff 

FUNC 

\Xl\l 

0 

a 

02 

bC 
03 

§ 

1 

0 

1.0000 
.9999 
.9994 
.9986 
.9976 
.9962 
.9945 
.9926 
.9903 
.9877 
.9848 
.9816 
.9782 
.9744 
.9703 
.9659 
.9613 
.9563 
.9511 
.9455 
.9397 
.9336 
.9272 
.9205 
.9136 
.9063 
.8988 
.8910 
.8830 
.8746 
.8660 
.8572 
.8480 
.8387 
.8290 
.8192 
.8090 
.7986 
.7880 
.7772 
.7660 
.7547 
.7431 
.7314 
.7193 
.7071 

Cotang. 

0 

90 
89 
88 
87 
86 
85 
84 
83 
82 
81 
80 
79 
78 
77 
76 
75 
74 
73 
72 
71 
70 
69 
68 
67 
66 
65 
64 
63 
62 
61 
60 
59 
58 
57 
56 
55 
54 
53 
52 
51 
50 
49 
48 
47 
46 
45 

0 

FIG.  11.  —  Diagram  illustrating  circular 
functions. 

SOLUTION    OF    TRIANGLES 
O 

^^                             a» 

0 

5 
6 

8 
9 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 
21 
22 
23 
24 
25 
26 
27 
28 
29 
30 
31 
32 
33 
34 
35 
36 
37 
38 
39 
40 
41 
42 
43 
44 
45 

0 

0.0000 
.0175 
.0349 
.0523 
.0698 
.0872 
.1045 
.1219 
.1392 
.1564 
.1737 
.1908 
.2079 
.2250 
.2419 
.2588 
.2756 
.2924 
.3090 
.3256 
.3420 
.3584 
.3746 
.3907 
.4067 
.4226 
.4384 
.4540 
.4695 
.4848 
.5000 
.5150 
.5300 
.5446 
.5592 
.5736 
.5878 
.6018 
.6157 
.6293 
.6428 
.6560 
.6691 
.6820 
.6947 
.7071 

0.0000 
.0175 
.0349 
.0524 
.0699 
.0875 
.1051 
.1228 
.1405 
.1584 
.1763 
.1944 
.2126 
.2309 
.2493 
.2680 
.2868 
.3057 
.3249 
.3443 
.3640 
.3839 
.4040 
.4245 
.4452 
.4663 
.4877 
.5095 
.5317 
.5543 
.5774 
.6009 
.6249 
.6494 
.6745 
.7002 
.7265 
.7536 
.7813 
.8098 
.8391 
,8693 
.9004' 
.9325 
.9657 
1.0000 

bC 

§ 
\ 

Infin. 
57  .  2900 
28  .  6363 
19.0811 
14.3007 
11.4301 
9.5144 
8  .  1444 
7.1154 
6.3138 
5.6713 
5  .  1446 
4.7046 
4.3315 
4.0108 
3.7321 
3.4874 
3  .  2709 
3.0777 
2.9042 
2.7475 
2.6051 
2.4751 
2.3559 
2  .  2460 
2.1445 
2.0503 
1.9626 
.8807 
.8041 
.7321 
.6643 
.6003 
.5399 
.4826 
.4282 
.3764 
.3270 
.2799 
.2349 
.1918 
.1504 
1.1106 
1.0724 
1.0355 
1.0000 

-A                                a                          & 

FIG.  12.  —  Right  triangle. 

Sin  A=~.  cosA=—  .  tan  A=~. 
b                   b                   c 

C=9Q°-A. 

.jS 

o 

^r                         /a. 

FIG. 

13.  —  Oblique  triangle. 

Given'  qu* 

j                    Formula. 

A,  a,  b       1 
C,a,b       I 

a,  b,  c 
A 

<z,  6,  c     Ar< 
A,  B,  c    Are 

a  sin  B 

sin  A  ' 

b  sin  A 
?          sin  B 

a 
?          tan  B        b  ?in  C 

a  —  b  cos  C 

If  a  =  £(a  +  6  +  c). 

.     1  A      |/  (s  —  6)  (s  —  c) 

am**.               bc        . 

or  cos  44     l/s(s~°> 

bc 

3a    Area=Vs(s—  a)(s—  6)(s—  c) 
ja    Area=£6c  sin  A. 

1 

j 

bC 

m 

H 

CIRCLES 
Circumference=27rft.  Area=r/?2    r=3.1416 

TABLES    AND    FORMULAS 


43 


1R* 

C  10    V 


'2  T   jj 
^g 


^s  o    • 
•3  o*  C* 

g  CO    0 


oo^co^b-t-iiorHi»ppt^^^»oopcoT^t^cocoi^iot>«poor>>--i 


t  ^ 


44  GENERAL    INSTRUCTIONS 


WRITTEN  NOTES 

All  notes  must  be  legible,  not  only  to  the  person  who  makes 
them,  but  to  anyone  else,  and  that  without  undue  effort  in 
deciphering  them.  A  reasonably  clear  handwriting  is  therefore 
essential  and  no  field  geologist  can  afford  to  use  an  illegible 
scrawl.  If  abbreviations  are  used  they  must  be  unambiguous, 
and  such  as  will  be  readily  understood  without  a  key — e.g.,  sand- 
stone, ss;  limestone,  li  or  Is;  quartz,  qtz;  quartzite,  qzt;  etc. 

Notes  must  be  definitely  localized  and  connected  with  a  map. 
The  exact  system  of  reference  employed  is  not  important,  pro- 
vided it  is  simple,  unambiguous,  and  consistently  used.  The 
locality  at  which  an  observation  is  made,  or  a  specimen  taken, 
should  be  marked  on  the  map  by  a  small  cross  or  dot,  or  in  case 
of  a  section  by  a  line  connecting  two  crosses  or  dots,  with  a 
reference  which  may  be  (a)  number  and  page  of  notebook,  (6) 
a  date  with  letter  indicating  separate  notes  for  that  day  (8-7-13-E), 
or  (c)  any  combination  of  numbers  and  letters  which  will  serve 
to  connect  the  point  on  the  map  with  the  written  note  and  enable 
either  to  be  found  readily  from  the  other. 

If  the  geology  is  so  complex  that  a  large  number  of  observa- 
tions must  be  made  within  a  small  area  and  the  reference  num- 
bers would  become  confused,  some  system  of  coordinates  may 
be  used,  viz.: 

(a)  The  atlas  sheet  is  dissected  on  meridians  and  parallels — 
10'  each  way  if  the  scale  is  1  :  125,000  and  5'  if  it  is  1  :  62,500; 
the  sections  are  numbered  and  pasted  on  a  page  of  a  notebook 
with  quadrille  ruling  to  sixths  of  an  inch;  the  rulings  about  the 
margin  of  the  map  are  continued  across  it  both  vertically  and 
horizontally;  letters  are  placed  across  the  top  and  numbers 
down  the  side.  A  dot  is  placed  on  the  map  at  the  point  of  obser- 
vation, and  the  notebook  reference  will  consist  of  an  abbrevia- 
tion of  the  quadrangle  name,  the  number  of  the  section  of  the 
atlas  sheet,  and  a  coordinate  letter  and  number — e.g.,  Ro-3-B13. 
If  several  points  fall  in  the  same  square  they  may  be  distinguished 
by  letters  indicating  the  quarter,  as  NW.,  NE.,  etc. 


WRITTEN    NOTES 


45 


(6)  The  atlas  sheet  is  dissected  and  pasted  in  the  notebook 
as  above.  Each  section  is  subdivided  on  meridians  and  parallels 
into  25  quadrangular  areas,  1'  or  2'  each  way,  depending  on  the 
scale,  and  each  of  these  into  9  quadrangular  areas.  The  last 


21 


31 


41 


51 


22 


32 


42 


52 


23 


43 


53 


24 


34 


44 


54 


25 


35 


45 


55 


FIG.  14. — Diagram  illustrating  subdivision  of  map  for  reference  numbers. 

subdivision  need  not  actually  be  made  on  the  map,  as  the  posi- 
tion of  a  point  within  the  1'  or  2'  areas  can  be  estimated.  The 
method  of  subdivision  and  numbering  is  shown  on  the  accom- 
panying diagram  (Fig.  14).  With  this  system  a  notebook  refer- 


46  GENERAL    INSTRUCTIONS 

ence  would  consist  of  an  abbreviation  of  the  quadrangle  name 
and  the  numbers  of  the  successively  smaller  subdivisions — e.g., 
Ro2-35-6. 

In  case  the  writing  of  specimen  numbers  would  confuse  the 
map  if  placed  on  its  face  a  convenient  method  of  location  is  to 
make  a  pin  hole  through  the  map  and  write  the  number  on  the 
back  of  the  notebook  page  on  which  it  is  mounted. 

When  a  topographic  map  is  not  available  the  descriptions  of 
the  locality  should  be  sufficiently  exact  and  complete  to  enable 
another  observer  to  find  the  locality  on  the  ground  without 
difficulty.  This  of  course  makes  it  necessary  for  the  observer 
to  know  exactly  where  he  is  when  he  makes  the  observation. 
If  he  does  not  know,  his  first  duty  is  to  find  out. 

Distances,  thicknesses,  and  dimensions  should  be  expressed  in 
definite  units  derived  from  actual  measurements  or  estimates — 
and  the  notes  should  state  which — and  not  by  means  of  indefinite 
or  relative  expressions  as  a  " short  distance,"  "a  considerable 
thickness,"  etc.  Estimates  should  be  accepted  only  where  the 
object  is  inaccessible  or  where  an  error  of  ten  per  cent  or  more 
is  permissible. 

Written  notes  should  be  dated  and  signed  and  should  contain 
some  information  as  to  the  conditions  under  which  the  obser- 
vations were  made — e.g.,  from  camp,  with  its  location;  on  foot; 
from  public  stage;  etc. 

Notes  should  be  carefully  classified  under  prominent  headings 
to  facilitate  indexing.  Clearness  and  ease  of  reference,  classi- 
fication, and  indexing  are  more  important  than  economy  of 
paper.  Headings  may  be  added  later,  to  save  time  in  the  field, 
but  the  habit  of  making  them  on  the  spot  is  a  good  one.  If  a 
loose-leaf  notebook  is  used,  only  one  subject  should  be  placed 
on  a  page,  so  that  the  leaves  may  be  assembled  and  classified 
under  various  subjects  and  localities.  In  this  case  the  classifi- 
fication  need  not  be  fixed  at  once  and  is  always  subject  to  change. 

The  record  of  facts  actually  observed  should  be  kept  separate 
and  distinct  from  conclusions  based  on  inference,  hypotheses, 
and  theories,  which,  however,  should  not  be  omitted  but  written 
down  as  they  occur  in  the  field.  They  can  easily  be  eliminated 
later  when — as  will  often  be  the  case — they  are  proved  incorrect. 


MAP  NOTES  47 

The  clear-cut  statement  of  a  hypothesis  often  initiates  the  search 
for  additional  data  which  may  prove  or  disprove  the  hypothesis. 


MAP  NOTES. 

For  field  notes  it  is  generally  desirable  to  use  a  map  enlarged 
by  photography  to  at  least  twice  the  scale  of  the  engraved  atlas 
sheet.  If  necessary  for  clearness  the  drainage  may  be  inked  in 
blue.  If  specified  on  the  requisition  the  photographs  can  be 
toned  to  give  brown  instead  of  black  lines,  which  adds  materially 
to  the  legibility  of  the  map  and  the  added  data.  The  paper 
used  should  be  of  the  best  quality  as  to  toughness  and  texture 
for  taking  ink.  Only  waterproof  inks  should  be  used  on  maps 
either  in  the  field  or  in  the  office. 

Boundaries  of  cartographic  units  must  be  placed  on  a  map 
in  the  field.  If  by  reason  of  inadequate  exposures  a  bound- 
ary cannot  be  accurately  located  on  the  ground,  no  amount 
of  study  in  the  office  will  increase  the  probability  of  correct 
location  and  the  benefit  of  many  significant  facts  of  soil,  topog- 
raphy, etc.,  will  be  lost.  If  a  guess  is  the  best  that  can  be  done, 
the  best  place  to  make  the  guess  is  on  the  ground.  Observed 
and  inferred  boundaries  should  be  discriminated — as  by  solid 
and  dotted  lines — and  a  special  symbol  should  be  used  for  various 
classes — e.g.,  comformable  contacts,  sedimentary  unconformities, 
faults,  intrusive  contacts,  etc.  The  map  should  show  the  exact 
point  at  which  the  observation  was  made.  It  frequently  hap- 
pens that  the  cartographic  units  which  are  to  appear  on  the 
published  map  are  not  determined  until  the  work  is  well  advanced 
or  until  office  determinations  have  been  mede.  It  is  highly 
desirable,  therefore,  to  locate  and  place  on  the  map  in  the  field 
not  only  those  boundaries  which  will  certainly  be  used,  but  also 
those  which  may  possibly  be  used. 

Structural  data  should  be  placed  on  the  map  in  the  field  by 
means  of  suitable  symbols  showing  dip  and  strike  of  beds,  struc- 
ture axes,  dip  of  faults,  etc.  These  symbols  should  indicate  as 
nearly  as  possible  the  exact  locality  at  which  the  observation 
was  made.  They  should  show  angles  of  dip  by  figures,  and 


48  GENERAL   INSTRUCTIONS 

should  be  sufficiently  abundant  to  enable  structure  sections  to 
be  drawn  wherever  desirable. 

Lithologic  and  stratigraphic  data  may  generally  be  placed  on 
Ibhe  map  in  the  field  by  means  of  abbreviations.  These,  however, 
should  always  be  supplemented  by  written  notes  and  the  exact 
locality  at  which  detailed  lithologic  observations  are  made  or 
sections  measured  and  described  should  be  indicated  on  the  map 
by  a  reference  number  or  letter  connecting  it  directly  with  the 
record  in  the  notebook.  By  the  use  of  a  hard  pencil  and  with 
careful  writing  a  surprisingly  large  amount  of  information  can 
in  this  way  be  placed  directly  on  the  map. 

Localities  at  which  collections  of  rocks,  minerals,  fossils,  etc., 
are  made  should  be  indicated  on  the  map;  also  generally  points 
from  which  photographs  are  taken,  with  the  direction  of  view 
indicated. 

Economic  data,  such  as  locations  of  mines,  quarries,  gravel 
pits,  undeveloped  deposits,  and  prospect  pits,  should  be  placed 
directly  on  the  map;  also,  unless  the  system  is  too  extensive 
and  complicated,  mills,  breakers,  ore  roads,  etc. 

Special  care  must  be  taken  to  secure  neatness  and  accuracy 
in  putting  these  data  on  the  map.  A  soft  or  blunt  pencil  should 
never  be  used  and  unnecessary  lines  should  not  be  drawn  in 
advance  of  the  determination  of  boundaries,  or  so  that  there 
will  subsequently  be  an  uncertainty  of  several  hundred  feet  in 
location.  The  use  of  colored  pencils  for  drawing  boundaries  is 
sufficient  evidence  of  inaccuracy  to  completely  condemn  a  piece 
of  geologic  work.  All  lines  determined  by  each  member  of  the 
party  should  be  inked  on  his  own  map  and  the  lines  determined 
by  other  members  of  the  party  should  be  transferred  to  it  in 
pencil. 

In  working  an  area  for  which  there  is  a  topographic  map  sev- 
eral copies  should  be  kept  in  the  stationery  box  and  used  for 
the  compilation  of  various  classes  of  data.  This  is  especially 
necessary  where  there  are  several  persons  in  the  party.  In  case 
a  photographic  enlargement  is  used  for  field  notes,  these  com- 
pilation sheets  should  be  the  regular  engraved  base.  As  the 
work  progresses  and  tentative  cartographic  units  are  decided 
on,  boundaries  should  be  transferred  to  an  undissected  base  map 


GRAPHIC  NOTES  49 

in  ink  and  the  areas  of  the  various  units  colored.  Pencils  may 
be  used  for  this  purpose,  or,  preferably,  transparent  Japanese 
water  colors.  The  latter  are  recommended  for  field  use  on 
account  of  their  convenience  and  the  excellent  results  which  they 
give.  This  map  should  always  be  brought  up  to  date  before 
moving  camp  or  station. 

There  should  be  a  route  map  showing,  by  means  of  different- 
colored  inks,  the  exact  route  followed  by  each  member  of  the 
party  each  day;  also  location  of  camps  or  other  stopping  places 
and  route  of  camp  outfit.  This  sheet  may  also  be  utilized  as  an 
index  of  collection  and  photograph  localities.  To  another  sheet 
should  be  transferred  in  ink  all  determined  boundaries  and  the 
principal  structural  data.  A  third  should  show  economic  data, 
location  of  mines,  quarries,  mills,  industrial  railroads,  tramways, 
etc.  If  many  topographic  corrections  and  additions  are  found 
necessary,  they  should  be  carefully  plotted  on  a  separate  sheet, 
in  ink,  for  transmission  to  the  topographic  branch. 

While  the  geologist  should  carefully  avoid  a  hypercritical 
attitude  toward  the  topographic  maps,  he  should  note  all  essential 
omissions  and  errors  and  wherever  practicable  furnish  data  for 
making  corrections.  Changes  in  culture,  particularly  roads, 
bridges,  railroads,  etc.,  should  be  accurately  noted.  When  an 
enlarged  photograph  is  used  in  the  field,  allowance  must  be  made 
for  the  difference  in  scale,  particularly  in  criticizing  contour 
generalizations.  The  map  may  be  entirely  adequate  for  the 
engraved  scale  and  yet  open  to  criticism  if  judged  on  an  enlarge- 
ment for  which  it  was  not  drawn. 


GRAPHIC  NOTES 

Sketches.  As  written  notes  are  intended  both  to  record  facts 
and  relations  and  to  present  a  word  picture  of  the  things  observed, 
they  can  generally  be  supplemented  with  great  advantage  by 
sketches  and  diagrams.  A  simple  sketch  is  frequently  the  most 
satisfactory  record  of  complex  relations,  particularly  where  the 
elements  are  on  a  small  scale,  so  that  their  relations  can  be  brought 
together  in  a  single  view.  Such  a  sketch  generally  requires  less 


50  GENERAL    INSTRUCTIONS 

time  than  a  complete  written  description  and  makes  definite  the 
relations  which  written  notes  can  only  vaguely  express;  more- 
over, its  construction  will  frequently  call  attention  to  important 
points  which  might  otherwise  be  overlooked.  The  habit  of 
'making  numerous  sketches  is  therefore  one  which  every  field 
geologist  should  acquire  and  constantly  practice.  It  is  not 
necessary  that  they  should  possess  artistic  merit,  but  merely 
that  they  should  be  clear  and  faithful  to  the  facts.  They  are 
essential  in  connection  with  observations  on  ore  deposits,  details 
of  contacts,  unconformities,  minor  structures,  etc.  The  broader 
relations  of  structure  to  relief  can  also  be  brought  out  by  sketches, 
but,  unfortunately,  more  skill  is  required  for  this  than  the  ordi- 
nary geologist  possesses. 

For  geologic  purposes  sketches  may  be  classed  as  plane  or 
perspective.  Plane  sketches  or  diagrams  are  those  in  which  rela- 
tions of  two  dimensions  only  are  represented.  They  are  sketch 
maps,  outlines,  profiles,  and  sections.  The  method  does  not 
differ  materially  from  topographic  mapping.  The  outline  or 
surface  to  be  sketched  is  examined  for  salient  points.  The  rela- 
tions of  these  among  themselves  are  noted  to  give  control.  Details 
are  then  filled  in  according  to  the  complexity  of  the  subject  and 
the  skill  of  the  draftsman.  In  securing  the  control  directions 
should  be  compared  with  the  vertical  or  horizontal,  and  should 
be  estimated  or  proportionately  measured  by  scaling  on  a  pencil 
held  at  arm's  length.  To  fill  in  the  work,  the  sketcher  traverses 
or  meanders  the  outlines  with  the  eye  and  plots  the  traverse 
between  control  points  by  hand.  The  best  practice  is  to  keep 
the  eye  most  of  the  time  on  the  object  and  to  train  the  hand 
to  follow  with  only  occasional  guiding  glances  at  the  paper.  The 
number  of  lines  should  be  the  least  that  will  express  the  relations. 

Perspective  sketching  is  like  plane  sketching,  except  that  the 
objects  drawn  must  be  projected  into  one  plane  from  their  rela- 
tive positions  in  three  dimensions.  An  imaginary  surface  is 
assumed  (the  ground  glass  of  the  visual  camera,  as  it  were),  and 
the  control  and  traversing  are  executed  as  if  the  objects  were 
all  seen  through  that  surface  and  thus  observed  on  it.  In  order 
to  express  greater  or  less  distance,  relative  size,  amount  of  detail, 
distinctness  of  line,  density  of  shadow,  etc.,  are  considered. 


GRAPHIC    NOTES  51 

Photographs.  The  use  of  the  camera  has  become  so  com- 
mon that  it  has  to  a  large  extent  displaced  sketching  by  geologists. 
While  a  photograph  is  valuable  as  a  record  of  facts  and  relations, 
it  should  be  remembered  that  the  camera  shows  no  discrimina- 
tion and  cannot  select  and  separate  the  important  from  the 
unimportant.  It  is,  therefore,  unless  conditions  are  exceptionally 
favorable,  generally  less  satisfactory  and  convincing  than  a 
sketch.  Moreover,  it  is  a  mistake  to  suppose  that  effective  pho- 
tography requires  less  skill  than  good  sketching.  The  operator 
needs  to  know  the  limitations  of  his  lens,  his  plate,  and  his  sub- 
ject in  order  to  judge  the  value  of  a  picture  before  taking  it. 
For  it  is  not  enough  to  take  a  picture.  There  should  be  an  obvious 
feature  or  features  related  to  the  object  of  study  and  of  such  a 
character  as  to  be  clearly  recognized  in  the  photograph.  That 
which  is  plain  to  the  narrow  vision  of  well-directed  observation 
may  become  an  insignificant  detail  through  a  wide-angle  lens. 
That  which  is  distinct  through  differences  of  color  may  be  obscure 
in  colorless  light  and  shadow.  Thus  photography  requires  care 
and  judgment,  and  these  qualities  are  the  more  important  because 
every  exposure  entails  future  expense  for  developing,  printing, 
cataloguing,  and  filing. 

In  the  'use  of  the  camera  in  the  field  two  purposes  should  be 
kept  in  mind — to  secure  (a)  an  accurate  record  of  facts — in 
other  words,  graphic  notes — and  (6)  material  for  illustration  of 
reports.  For  the  first  purpose,  since  the  photographs  are  pri- 
marily for  the  geologist  himself,  attention  should  be  given  to 
bringing  out  the  particular  facts  and  relations  desired  in  order 
to  supplement  the  written  notes,  and  the  photographs  should 
in  turn  be  supplemented  by  written  notes  and  sketches.  For 
the  second  purpose  attention  should  also  be  given  to  "  composi- 
tion" and  the  possibilities  of  reproduction.  The  reader  who  sees 
the  result  may  be  entirely  unfamiliar  with  the  region  described, 
and  the  view  should  so  far  as  possible  set  the  main  features  clearly 
before  him. 

A  critical  examination  of  the  U.  S.  Geological  Survey  photo- 
graphs for  the  selection  of  views  illustrating  geologic  and  physio- 
graphic types  has  brought  out  the  fact  that  in  most  cases  not 
sufficient  care  has  been  exercised  in  selecting  the  point  of  view. 


52  GENERAL    INSTRUCTIONS 

This  care  should  be  proportionate  to  the  interest  of  the  subject. 
Important  adjuncts,  the  explanatory  settings  of  a  picture,  are 
often  lost  through  being  too  near  to  the  object  and  desirable 
detail  through  being  too  far  away  from  it.  If  a  convertible  lens 
is  used,  the  combination  should  be  employed  which  is  best  adapted 
to  secure  a  complete  view  with  the  most  detail. 


TRAVERSE  NOTES 

Exact  location,  both  horizontal  and  vertical,  is  essential  in 
nearly  all  forms  of  geologic  field  work.  If  this  is  not  furnished 
by  a  topographic  map  it  must  be  supplied  by  the  geologist  him- 
self through  some  form  of  traverse.  Even  the  best  topographic 
maps  will  show  some  areas  in  which  location  is  impossible  with- 
out traverse.  The  method  of  making  a  traverse  should  there- 
fore be  familiar  to  all  field  geologists. 

Notebook  traverse.  The  general  direction  of  the  proposed 
traverse  having  been  determined,  select  a  point  on  the  edge  of 
the  notebook  page  so  that  this  direction  will  pass  through  its 
center.  If  the  point  of  starting  is  identifiable  on  the  map,  indi- 
cate it  there  by  a  suitable  reference  number;  take  a  compass 
sight  to  some  object  in  the  direction  to  be  traversed  and  lay 
this  down  on  the  notebook  page  with  a  protractor;  measure  the 
distance  by  pacing  or  otherwise  to  the  object  sighted,  and  lay 
off  this  distance  on  the  scale  selected;  from  this  new  point  take 
a  second  compass  sight,  lay  it  off  with  the  protractor,  and  pro- 
ceed as  before.  Relief  adjacent  to  the  line  of  traverse  should 
be  indicated  by  sketch  contours  with  sufficient  care  to  give  a 
general  idea  of  its  character,  and  both  drainage  and  culture  should 
be  indicated.  These  features  should  be  given  with  sufficient 
accuracy  to  check  the  topographic  map,  or  in  the  absence  of  a 
map  to  supply  its  place.  The  larger  scale  permits  fuller  geologic 
notes  to  be  written  on  a  notebook  traverse  than  on  a  topographic 
map.  The  scale  selected  should  be  such  as  to  give  a  simple  rela- 
tion between  the  pace  or  other  unit  of  distance  and  the  notebook 
ruilng — a  convenient  scale  is  40  four-step  units  to  one  square 
(one-sixth  or  one-fifth  inch).  The  scale  used  should  be  noted 


TRAVERSE   NOTES  53 

on  each  page  containing  the  whole  or  part  of  a  traverse,  and 
particularly  the  equivalent  in  feet  and  inches  of  the  unit  employed. 
The  method  and  results  of  a  notebook  traverse  are  shown  in 
Fig.  15,  which  represents  a  single  day's  work  and  covers  about 
6  square  miles  of  moderately  complicated  geology,  with  11.5 
miles  of  traverse.  The  geologic  mapping  is  sufficiently  close 
for  publication  on  the  1  :  125000  scale  but  not  on  the  1  : 62500, 
for  which  at  least  50  per  cent  more  locations  on  formation  boun- 
daries should  have  been  made. 

The  traverse  was  started  at  Rock  Spring  P.  O.,  where  a  line 
by  HBG  was  started   eastward   on  the   same   day.     This  point 
was  located  near  the  upper  right-hand  corner  of  the  notebook 
page,  since  the  area  to  be  covered  lay  to  the  southwest.     At  the 
end  of  the  second  course  a  sight  was  taken  to  a  limestone  quarry 
and    the    distance    to    it    paced.     A    description    of   the   quarry, 
arranged  under  the  headings  given  in  Schedule   8,  was  written 
in  the  notebook  HQ  and  given  a  designation  consisting  of  the 
date  and  a  letter — 8/30 A.     Returning  to  the  main  road  the  line 
was  continued  southward  to  a  point  where  a  trail  started  up  the 
end  of  the  ridge  to  the  west.     The  traverse  was  carried  along 
this  trail  following  the  crest  of  the  ridge  to  its  highest  point, 
and  continued  down  the  point  to  the  contact  of  a  formation  known 
to  extend  several  miles  to  the  northwest.     Written  notes  were 
made  at  B.  and  C.  and  a  detailed  section  was  measured  at  D. 
Returning  to  the  high  point  the  traverse  was  carried  along  the 
ridge  forming  the  southwestern  side  of  a  pitching  syncline,   to 
the  main  valley  road  where  it  failed  to  close  by  about  370  feet. 
This  illustrates  a  common  tendency  to  overestimate  paced  dis- 
tances  in   ascending   and   underestimate   them   in   descending   a 
slope.     The  main  line  was  then  continued  south  to  Alexander 
Gap,  tieing  at  that  point  with  HBG  line  of  the  previous  day,  and 
at  Colvin  Station  with  RD  line  also  of  the  previous  day.     From 
Alexander  Gap  a  circuit  was  made  to  the  west  with  several  spur 
lines  to  determine  the  structure  and  distribution  of  the  forma- 
tions within  a  small  area  of  exceptional  complexity.     This  circuit 
tied  with  the  main  line  at  Colvin  with  an  error  of  350  feet.    Finally, 
from  Colvin  a  line  was  run  across  the  strike  about  midway  between 
the   two    circuits.     Sketch   contours   were    drawn   only   to    show 


bk 

BG 


*1 


& 


A* 


to 


'ft 


Ofi 


ffi 


*& 


M 


_bl 


X 


X 


5 


1? 


JUAK 


tr  ^a 


Fio.  15. — Example  illustrating  notebook  traverse. 


54 


TRAVERSE    NOTES  55 

form  and  relative  elevation  of  surface  with  no  attempt  to  deter- 
mine absolute  altitudes.  All  formation  boundaries  and  faults 
were  drawn  as  determined  on  the  ground  and  sketched  in  between 
observed  points  in  conformity  with  the  topography. 

Sketching-case  traverse.  For  rapid  traverses  where  greater 
accuracy  is  required  than  the  notebook  method  permits,  the  use 
of  a  sketching  case  may  be  found  advantageous.  This  instrument, 
as  modified  by  Glenn  S.  Smith,  is  shown  in  Fig.  16.  It  consists 
essentially  of  a  small  board  8  by  12  inches  in  size  provided  with 
a  roller  at  each  end  carrying  a  long  strip  of  transparent  paper. 
A  compass  box  carrying  a  3-inch  floating  card  graduated  to  360° 
and  furnished  with  rifle  sights  is  attached  to  one  corner.  Under 
the  paper  is  a  circular  plate  which  can  be  rotated  and  moved 
laterally  across  the  board,  and  on  which  is  attached  a  card  6 
inches  in  diameter  containing  a  combined  protractor  and  scale. 
The  protractor  is  graduated  to  degrees  and  numbered  from  1 
to  360.  A  radius  extends  from  the  center  to  each  degree  and 
these  are  divided  into  equal  parts  by  a  series  of  concentric  circles, 
so  that  any  radius  may  be  used  as  a  scale.  Protractor  cards  are 
furnished,  suitably  divided  for  any  scale  desired,  as  1  to  45,000, 
1  to  90,000,  or  tenths  of  an  inch. 

To  use  the  sketching  case,  attach  the  paper  to  the  rollers,  wind- 
ing all,  except  enough  for  fastening,  on  the  upper  roller.  Deter- 
mine the  general  direction  of  the  traverse  to  be  made,  revolve 
'the  protractor  plate  until  the  degree  corresponding  to  this  direc- 
tion comes  opposite  the  index  line  over  the  clamp  screw,  and 
clamp  the  plate  in  place.  Draw  a  line  on  the  paper  through  the 
zero  and  180°  points;  this  line  will  be  the  magnetic  meridian. 
Move  the  protractor  plate  so  that  its  center  is  near  the  middle 
of  the  paper;  the  station  occupied  is  indicated  by  a  point  over 
the  center  of  the  protractor;  sight  to  the  next  station  to  be 
occupied  and  draw  a  line  on  the  radius  corresponding  to  the  com- 
pass reading;  measure  the  distance  to  this  station  and  plot  it 
by  means  of  the  scale  on  this  radius;  move  the  paper  down  until 
the  point  indicating  the  second  station  is  opposite  the  center 
of  the  protractor,  and  move  the  protractor  plate  sideways  until 
its  center  coincides  with  this  point;  sight  to  the  next  station 
and  to  any  points  to  be  intersected,  and  draw  lines  on  the  radii 


56 


GENERAL    INSTRUCTIONS 


a 


I 


PLANE-TABLE    NOTES  57 

corresponding  to  the  compass  readings.  Relief,  culture,  and 
geologic  data  are  recorded  exactly  as  in  a  notebook  or  plane- 
table  traverse. 

Map  traverse.  In  case  an  enlarged  photograph  of  the  base 
map  is  used  in  the  field  it  is  frequently  desirable  to  secure  accurate 
location  by  means  of  a  traverse  plotted  directly  on  the  map.  If 
the  magnetic  declination  is  more  than  3°  the  magnetic  meridians 
should  be  drawn  on  the  map  and  used  instead  of  the  true  meridians 
for  plotting  compass  directions.  More  care  is  required  in  scaling 
distances  than  in  making  a  notebook  traverse,  on  account  of 
the  smaller  scale,  but  a  decided  advantage  is  gained  in  that  the 
notes  need  not  be  transferred. 


PLANE-TABLE  NOTES 

While  the  plane  table  is  primarily  a  topographic  instrument, 
it  is  under  some  circumstances  utilized  in  geologic  work.  In  the 
absence  of  a  topographic  map,  or  where  topographic  and  geologic 
work  are  being  carried  on  at  the  same  time,  the  plane-table 
method  with  or  without  supplementary  notebook  traverses  may 
be  adopted.  It  is  much  more  accurate  than  the  notebook  traverse 
and  hence  should  be  used  for  purposes  of  control  even  where  the 
greater  part  of  the  work  is  done  by  more  rapid  but  less  accurate 
methods.  It  is  practically  indispensable  in  case  it  becomes  neces- 
sary to  make  a  detailed  topographic  map  of  a  small  area — for 
example,  a  small  mining  district.  In  such  a  district,  where  the 
geologic  structure  is  apt  to  be  exceptionally  complex  and  a  high 
degree  of  accuracy  is  required,  a  plane  table  may  be  used  with 
advantage,  even  with  a  good  topographic  map. 

The  geologist  will  rarely  need  to  make  use  of  the  more  elaborate 
forms  of  the  instrument,  such  as  the  Johnson  head  and  telescopic 
alidade.  The  traverse  plane  table  with  open-sight  alidade,  will 
answer  all  ordinary  needs.  This  consists  of  a  board  about  15 
inches  square,  into  one  edge  of  which  is  set  a  narrow  box  contain- 
ing a  compass  needle.  The  table  is  supported  by  a  light  tripod 
and  is  leveled  by  means  of  the  legs.  A  screw  fastens  the  board 
to  the  tripod  head  and  it  is  held  in  adjustment  in  azimuth  by 


58  GENERAL    INSTRUCTIONS 

friction.  The  table  is  oriented  by  means  of  the  compass  needle; 
that  is,  it  is  turned  until  the  needle  rests  opposite  the  zero  marks 
in  the  compass  box  and  is  thus  always  made  parallel  to  its  former 
positions,  provided  the  magnetic  declination  remains  constant. 
The  alidade  consists  of  a  graduated  brass  ruler,  6  to  12  inches 
long,  with  folding  sights.  Ordinary  drawing  paper  backed  with 
cloth  is  used  and  is  attached  to  the  board  by  thumb  tacks. 

In  making  a  topographic  map  or  a  combined  topographic  and 
geologic  map  the  following  procedure  is  employed.  The  instru- 
ment is  set  up  at  the  initial  point,  roughly  leveled,  and  oriented. 
A  point  is  marked  on  the  paper  to  represent  the  initial  station, 
the  edge  of  the  alidade  is  placed  on  it  and  pointed  to  the  object 
selected  as  the  second  station,  and  a  line  is  drawn  in  that  direction. 
Sights  are  also  made  and  lines  drawn  in  the  direction  of  any 
prominent  objects  which  it  is  desired  to  locate,  such  as  rock  out- 
crops, hilltops,  buildings,  etc.  The  instrument  is  then  taken 
to  the  station  sighted,  the  distance  being  measured  and  noted, 
and  is  either  set  up  at  this  second  station  or  moved  to  a  third 
station,  from  which  the  second  is  visible.  The  distance  from  the 
first  to  the  second  station  is  laid  off  on  the  line  connecting  the 
two,  on  the  scale  selected.  This  gives  the  point  on  the  paper 
representing  the  position  of  the  second  station  and  may  be  occu- 
pied by  setting  up  the  instrument  as  at  the  initial  point;  or  if 
the  instrument  is  moved  to  the  third  station,  after  orienting,  the 
edge  of  the  alidade  is  placed  on  the  second  station  point  and 
sighted  to  that  point.  The  line  drawn  will  then  connect  the 
second  and  third  station  points,  and  the  position  of  the  third  is 
determined  by  laying  off  the  measured  distance  between  them. 
From  each  station  occupied  sights  are  made  to  objects  to  be 
located  and  intersections  of  the  lines  drawn  from  the  various 
stations  will  give  their  locations.  At  least  three  intersections 
should  be  secured  on  each  object.  Aneroid  elevation  should  be 
noted  at  each  station  and  at  intermediate  points  when  necessary. 
Drainage  and  culture  should  be  sketched  and  all  prominent  geo- 
logic features  located  while  the  traverse  is  being  run.  The  con- 
tours may  be  sketched  at  the  same  time,  or  this  may  be  done  sub- 
sequently by  the  same  man,  or  one  more  experienced,  after  the 
traversing  is  completed.  The  geologic  boundaries  and  other 


PLANE-TABLE    NOTES  59 

necessary  geologic  data  may  be  also  placed  on  the  map  during 
the  traversing  or  after  its  completion. 

Supplementary  notebook  traverses  in  the  area  covered  by  the 
plane-table  sheet  should  be  transferred  to  that  sheet  in  the  field, 
in  order  to  bring  together  geologic  observations  in  their  proper 
relations  during  the  progress  of  the  work. 

The  traverse  method  in  plane-table  work  will  be  the  one  com- 
monly employed  by  the  geologist,  but  under  certain  conditions 
it  may  be  desirable  to  make  all  locations  by  intersection.  Such 
conditions  are  afforded  by  an  unforested  region  of  considerable 
relief,  particularly  one  in  which  there  is  much  local  magnetic 
attraction,  as  is  usually  the  case  where  coal  beds  have  been 
burned  on  the  outcrop. 

A  base  line  is  measured  from  which  suitable  points  may  be 
sighted  for  expansion  by  the  development  of  a  series  of  triangles. 
The  base  should  be  measured  by  tape  or  by  stadia,  using  sights 
not  more  than  500  feet,  on  as  level  ground  as  possible,  and  so 
located  that  the  ends  are  intervisible.  Special  care  should  be 
exercised  in  determining  both  the  length  and  direction  of  the  base 
line  and  both  foresights  and  backsights  used  to  obviate  error 
due  to  possible  local  attraction.  The  length  of  the  base  will 
depend  on  local  conditions,  but  one  mile  will  generally  be  ample. 
The  points  selected  for  expansion  of  the  base  should  be  so  located 
as  to  give  sufficiently  wide  angles  for  accurate  intersections. 

Having  established  a  sufficient  number  of  control  points  within 
the  area  to  be  mapped,  station  locations  are  obtained  by  setting 
up  the  plane  table,  and  drawing  backsights  from  several  control 
points.  The  compass  needle  may  ordinarily  be  used  for  orien- 
tation, but  if  there  is  local  attraction  it  will  at  once  be  recognized 
by  failure  to  obtain  a  good  intersection  on  the  first  orientation, 
and  the  location  must  be  found  by  the  "  three-point "  method. 
The  following  graphic  solution  of  the  problem  is  most  convenient 
for  field  use.*  Orient  the  table  as  nearly  as  possible,  and  draw 
lines  from  three  located  points  which  will  intersect  to  form  a 
" triangle  of  error."  Now  rotate  the  table  slightly  and  draw 
lines  from  the  same  three  points.  A  new  triangle  of  error  will 

*  For  a  full  explanation  of  the  solution  see  Geo.  B.  Chittenden,  9th  Ann. 
Kept.,  Hayden  Survey,  1875,  p.  365. 


60 


GENERAL    INSTRUCTIONS 


be  formed  similar  to  the  first.  Connect  similar  angles  of  these 
two  triangles  and  the  lines  extended  will  intersect  in  a  common 
point,  which  will  be  the  correct  position  of  the  station.  The 
table  can  now  be  correctly  oriented  by  placing  the  edge  of  the 
alidade  upon  this  point  and  one  of  the  located  points  and  rotat- 
ing the  table  until  they  fall  in  line.  This  method  is  most  readily 
applied  when  the  station  is  (a)  within  the  triangle  formed  by  the 
three  located  points,  or  (6)  outside  of  this  triangle  but  within 
the  circle  drawn  through  these  points.  The  position  of  the 
triangles  of  error  in  these  two  cases  is  shown  in  Fig.  17. 


Fio.  17. — Diagram  illustrating  triangle  of  error. 

In  case  a  small  area  is  being  worked  in  detail,  as  a  mining  dis- 
trict, and  a  good  topographic  map  is  available,  the  plane  table 
may  be  used  with  advantage  for  securing  exact  location  on  the 
map.  For  this  purpose  the  map  should  be  enlarged  to  a  con- 
venient scale  by  photographing  if  necessary,  and  a  mounted  copy 
fastened  to  the  board  with  thumb  tacks,  the  magnetic  meridian 
being  placed  exactly  parallel  to  the  edge  of  the  board  containing 
the  compass  box.  If  the  angle  of  magnetic  declination  is  large, 


PROFILE    NOTES  61 

it  is  necessary  to  place  the  sheet  askew  upon  the  board,  a  con- 
dition which  reduces  the  size  of  the  sheet  that  can  be  used  and 
is  otherwise  objectionable.  To  obviate  this  difficulty  the  map 
is  tacked  on  the  board  with  the  true  meridian  parallel  to  its  edge, 
(a)  The  compass  box,  instead  of  being  fastened  rigidly  to  the  board, 
is  hinged  at  one  end  and  the  other  end  is  supported  by  a  grad- 
uated arm  which  passes  under  the  board  and  on  which  it  may 
be  swung  out  and  clamped  at  an  angle  equal  to  the  local  magnetic 
declination;  or  (6)  the  magnetic  meridian  is  marked  on  the  map 
and  the  board  is  oriented  by  placing  the  edge  of  a  box  compass 
against  this  line  and  turning  the  board  until  the  needle  stands 
at  the  north  and  south  points  on  the  circle.  The  orientation  is 
effected  more  accurately  and  conveniently  by  the  use  of  a  special 
alidade  devised  by  L.  C.  Graton  and  differing  from  the  ordinary 
alidade  in  having  a  compass  box,  similar  to  the  one  ordinarily 
attached  to  the  plane  table,  set  on  the  base,  the  sights  folding 
down  on  one  side  of  the  box.  The  edge  of  this  alidade  is  placed 
on  the  line  marking  the  magnetic  meridian  and  the  board  is 
turned  until  the  needle  rests  at  the  zero  points.  The  alidade  is 
then  used  as  the  ordinary  instrument.  The  advantages  of  this 
modification  are  that  greater  accuracy  is  secured  by  having  a 
longer  edge  for  adjustment  to  the  meridian  line  than  when  the  com- 
pass is  used,  and  that  time  is  saved  by  having  one  less  instrument 
to  handle.  After  the  board  is  oriented  two  or  more  points  which 
lie  within  the  mapped  area,  and  which  can  be  identified  on  the 
map  are  selected.  Sights  are  taken  to  these  points  and  the  inter- 
section of  the  lines  fixes  the  point  at  which  the  instrument  is  set 
up. 


PROFILE  NOTES 

A  convenient  method  of  recording  observations  under  special 
conditions  has  been  devised  by  M.  R.  Campbell  and  used  exten- 
sively in  the  Eastern  and  Central  coal  fields.  The  conditions  for 
its  use  are  (a)  approximately  horizontal  bedding — dips  less  than 
5° — and  (fr)  a  good  topographic  base  map  with  numerous  deter- 
mined elevations.  It  is  particularly  useful  where  the  strata  con- 


62  GENERAL    INSTRUCTIONS 

sist  of  similar  beds  frequently  repeated  and  poor  in  fossils,  so  that 
the  exact  stratigraphic  position  of  a  particular  bed  cannot  be 
determined  by  inspection  alone,  and  where,  in  addition,  the  rocks 
,  are  not  well  exposed.  The  method  consists  essentially  in  con- 
structing a  continuous  sketch-profile  section  for  all  routes  traversed, 
the  geologic  data  being  placed  directly  upon  this  profile  by  graphic 
conventions  or,  if  written,  referred  to  it. 

A  notebook  having  quadrille  ruling  to  sixths  of  an  inch  is  used. 
A  convenient  vertical  scale  is  selected — say  120  feet  to  the  inch, 
or  20  feet  to  each  square  of  the  ruled  page.  No  attempt  is  made 
to  preserve  uniformity  in  horizontal  scale. 

The  following  is  the  procedure.  Begin  at  a  point  certainly 
identifiable  on  the  map,  as  a  crossroads  or  stream  crossing.  Place 
a  reference  on  the  map  consisting  of  the  number  of  the  notebook 
page  used  (numbers  of  left-hand  pages  are  used  for  both  left  and 
right)  and  a  letter  indicating  the  number  of  the  station — e.g.,  6a 
Place  the  same  letter  at  a  point  on  the  left-hand  margin  of  the 
page  in  such  a  position  that  the  highest  point  on  the  profile  drawn 
to  the  scale  selected  will  come  below  the  upper  edge  of  the  page. 
The  altitude  of  the  starting-point — determined  directly  from  the 
map  or  from  the  aneroid  previously  set  at  the  nearest  bench 
mark — determines  the  position  of  the  point  between  rulings  and 
also  the  altitudes  represented  by  the  rulings  adjacent,  several 
of  which  should  be  marked  on  the  margin  of  the  page.  For 
example,  if  the  elevation  of  the  starting  point  is  868  feet,  the  ruling 
below  it  will  be  marked  860,  the  one  above  880,  etc.  Proceed 
from  the  starting  point  along  any  route  which  can  be  identified 
on  the  map  as  a  road  or  trail  to  the  first  decided  change  in  slope, 
noting  elevations  of  outcrops  and  contacts  and  of  the  second 
station.  Plot  the  profile  to  this  point,  using  the  vertical  scale 
selected,  and  indicating  by  appropriate  symbols  and  at  their 
proper  altitudes  all  exposures  and  contacts  seen.  Symbols  for 
shale,  sandstone,  conglomerate,  limestone,  coal,  etc.,  should  be 
carefully  selected  and  used  consistently.  Proceed  to  the  next 
decided  change  in  slope  and  plot  the  profile  and  outcrops  as  before. 
When  a  second  point  is  reached  which  can  be  certainly  identified 
on  the  map,  place  a  new  reference  on  the  map  at  that  point  and 
a  corresponding  letter  on  the  profile.  In  case  the  aneroid  does 


LAND-CLASSIFICATION    SURVEYS  63 

not  give  sufficiently  accurate  results  it  should  be  supplemented 
by  the  hand  level. 

As  the  work  progresses,  the  positions  of  various  outcrops  of 
beds  which  have  been  recognized  at  several  places  should  be  con- 
nected, and  these  connecting  lines  will  indicate  the  direction  of 
dip  and  of  structure  axes,  though  of  course  on  a  very  much  exag- 
gerated scale.  They  will  also  indicate  the  approximate  position 
of  important  horizons,  as  formation  boundaries  arid  coal  beds, 
which  may  be  so  nearly  concealed  that  they  would  otherwise 
be  overlooked. 

As  a  final  result  the  method  yields  a  complete  network  of 
intersecting  profiles  which  enable  the  geologist  to  identify  with 
certainty  particular  beds  or  horizons  which  have  not  sufficiently 
well-marked  characteristics  for  identification  by  ordinary  means. 

The  profile  notes  require  special  treatment  in  the  office  to 
deduce  from  them  the  true  structure,  underground  contours, 
and  exact  location  of  boundaries,  but  this  matter  need  not  be 
discussed  here.  In  addition  to  the  data  shown  graphically  on 
the  profile  there  should  always  be  supplementary  written  notes, 
describing  lithologic  character,  nature  of  contacts,  economic 
materials,  etc.  These  notes  are  placed  on  any  unused  portion 
of  the  page  or  on  a  separate  page,  and  connected  with  the  profile 
by  reference  numbers.  At  the  same  time  that  the  profiles  are 
being  constructed,  formation  boundaries,  so  far  as  they  can  be 
determined,  should  be  placed  on  the  map  as  when  other  methods 
are  used. 

The  results  of  the  profile  method  are  illustrated  in  Fig.  18. 


LAND-CLASSIFICATION  SURVEYS 

In  regions  which  have  been  subdivided  by  the  public-land 
system  but  not  surveyed  topographically  or,  if  surveyed,  in  which 
land  lines  are  not  accurately  shown  on  the  topographic  map,  it 
may  be  necessary  to  make  a  combined  geologic  and  topographic 
survey — particularly  for  the  purpose  of  classifying  the  public 
lands  as  mineral  and  non-mineral.  In  such  surveys  the  one 
absolutely  essential  condition  is  that  both  topography  and  geology 


64  GENERAL  INSTRUCTIONS 

shall  be  tied  to  the  land  lines  and  mapped  in  their  proper  relations 
to  the  land  subdivisions.  To  comply  with  this  essential  con- 
dition a  sufficiently  large  proportion  of  the  land  corners  must 
be  actually  found  to  give  the  necessary  control — to  enable  the 
geologist  to  say  with  assurance  in  what  township,  section,  and 
forty  any  point  on  the  ground  is  located.  Such  surveys,  there- 
fore, differ  from  the  ordinary  combined  topographic  and  geologic 
surveys  described  on  the  foregoing  pages  in  having  a  fixed  hori- 
zontal control  already  established  on  the  ground. 

All  available  information  which  will  be  of  assistance  in  locat- 
ing corners  and  adding  horizontal  and  vertical  control  should 
be  in  hand  before  beginning  work  on  any  township.  Much  of 
this  information  can  often  be  procured  by  correspondence  before 
taking  the  field  and  later  supplemented  by  personal  visits  to 
local  land  offices,  county  surveyor's  offices,  etc.  The  most 
important  is  derived  from  (a)  township  plats  and  field  notes  of 
the  original  land  surveys,  from  the  General  Land  Office,  also  brief 
descriptions  of  corners  from  records  of  surveyors-general;  (6) 
maps  and  profiles  of  surveys  for  railroads,  reservoirs,  canals, 
pipe  lines,  etc.,  obtained  from  the  files  of  the  Land  Office  and 
Reclamation  Service,  or  from  railroad  engineers;  (c)  county 
road  maps,  town  plats,  claim  maps,  private  ranch  maps,  etc., 
which  can  usually  be  obtained  from  the  county  surveyor's  office. 

After  a  Government  corner  on  the  township  to  be  surveyed 
has  been  found  and  identified,  additional  corners  sufficient  to 
establish  control  must  be  found.  The  method  of  marking  cor- 
ners given  in  the  General  Land  Office  " Manual  of  Surveying," 
which  can  be  secured  from  that  office,  should  be  thoroughly  famil- 
iar to  everyone  working  in  a  region  of  public-land  surveys. 

In  a  thinly  settled  region  the  best  method  of  finding  corners 
is  by  traversing  the  township  and  section  lines.  If  accurate 
sights  are  taken  with  the  compass  on  a  Jacob's  staff  or  with 
the  plane-table  alidade,  and  care  is  taken  in  pacing,  the  radius 
of  the  circle  within  which  the  next  corner  must  be  sought  is  so 
reduced  that  if  a  corner  was  ever  established  in  a  proper  manner 
the  chances  of  finding  it  are  good.  Other  methods  of  locating 
the  point  on  the  ground  where  the  corner  ought  to  be  found 
may  be  used,  as  by  triangulation  with  plane  table  or  by  meander 


LAND-CLASSIFICATION   SURVEYS  65 

traverse,  but  these  require  more  skill  than  section-line  traverses 
and  should  be  used  only  in  exceptionally  rough  country  or  where 
the  corners  are  conspicuously  marked.  Valuable  information 
relative  to  the  status  of  land  corners  in  a  given  district  can 
frequently  be  obtained  from  county  surveyors. 

The  greater  part  of  the  topographic  sketching  and  determina- 
tion of  geologic  boundaries  and  structure  can  be  done  from  the 
traverses  required  in  the  location  of  corners,  but  additional 
locations  of  important  topographic  and  geologic  features  should 
be  made  by  traverse  or  intersection.  Roads,  trails,  and  streams 
can  generally  be  sketched  with  sufficient  accuracy  from  section 
lines,  but  if  not,  they  should  be  traversed.  It  should  be  remem- 
bered that  the  unit  of  land  classification  is  the  sixteenth  of  a 
section — that  is,  a  40-acre  tract;  it  will  therefore  generally  be 
essential  in  coal-land  surveys  to  traverse  the  principal  coal  out- 
crops and  prospect  them  wherever  necessary  to  determine  their 
thickness. 

Blank  township  plats  should  be  used  for  all  graphic  notes, 
preferably  those  on  the  scale  of  two  inches  to  the  mile,  though 
half  of  this  scale  may  be  used  if  the  geologist  possesses  the  neces- 
sary drafting  skill.  The  plats  may  be  folded  for  use  in  a  note- 
book or  fastened  on  a  plane  table.  The  blank  plats  are  ruled 
to  correspond  to  a  theoretically  perfect  township,  and  do  not 
provide  for  the  irregularities  made  necessary  by  the  adjustment 
of  actual  surveys  along  township  exteriors  and  between  surveys 
made  at  different  times.  These  irregularities  can  be  obtained 
from  the  original  Land  Office  plats,  a  copy  of  which  should  be 
in  hand,  and  should  appear  on  the  completed  plat;  otherwise 
both  topography  and  geology  will  be  distorted.  Care  should  be 
exercised  to  see  that  the  work  done  by  different  men  is  con- 
nected, any  lack  of  perfect  correspondence  in  topography  or 
geology  between  townships  or  portions  of  townships  being  always 
adjusted  before  leaving  the  field. 

As  in  other  kinds  of  surveys,  special  conditions  will  be  met 
that  will  require  more  refined  methods  than  those  outlined 
above1,  as  the  stadia  for  making  horizontal  locations  and  the 
level  for  vertical  control.  The  work  then  becomes  primarily 
topographic  and  need  not  be  considered  here. 


66  GENERAL    INSTRUCTIONS 

In  some  cases  it  may  be  impossible  to  find  any  corners  in  one 
or  several  adjoining  townships,  either  because  they  were  not 
properly  marked,  or  for  other  reasons.  The  lands  in  such  town- 
ships cannot  be  finally  classified  until  they  have  been  resub- 
divided.  While  it  may  sometimes  be  necessary  to  continue  work 
in  them  in  order  to  trace  formations,  the  necessity  for  subsequent- 
adjustment  of  the  geology  and  topography  to  the  land  lines 
should  be  kept  in  mind. 

Each  township  plat  as  completed  in  the  field  should  show 
(a)  legal  designation;  (6)  name  of  the  person  or  persons  who 
did  the  work,  and  the  part  for  which  each  is  responsible;  (c) 
inclusive  dates  and  number  of  days  spent  by  each  person;  (d) 
magnetic  declination  to  nearest  degree;  (e)  by  legend,  all  dis- 
tinctive symbols  used,  contour  interval,  and  geologic  formations 
in  proper  sequence;  (/)  relief  by  means  of  contours;  (g)  drain- 
age, perennial  and  intermittent,  lakes,  swamps,  irrigation  ditches, 
and  playas;  (h)  culture — railroads,  roads,  trails,  houses,  etc.; 
(i)  geologic  boundaries,  which  must  be  put  in  carefully  with  hard 
pencil  and  then  inked;  (/)  coal  outcrops,  shown  by  a  continuous 
heavy  inked  line  where  seen,  and  by  a  broken  line  where  inferred; 
(k)  all  found  corners  (by  special  symbol)  and  all  lines  traversed; 
(0  location  of  lines  along  which  profiles  were  made ;  (ra)  reference 
numbers  to  notebook  for  indicating  location  of  observations 
recorded  in  written  notes,  specimens,  fossil  localities,  etc. 


MINE  SURVEYS 

In  the  study  of  an  ore  deposit  the  first  essential  is  to  procure 
a  map  of  the  underground  workings.  If  a  mine  map  has  been 
made,  the  officers  of  the  company  will  nearly  always  permit  the 
geologist  to  make  a  tracing.  This  may  be  done  on  tracing  linen, 
but  where  the  study  is  incident  to  other  work  and  the  geologist 
is  not  equipped  with  such  drawing  material,  tissue  paper  may 
be  used,  or  even,  if  this  is  not  at  hand,  ordinary  wrapping  paper, 
the  mine  map  being  pinned  below  the  paper  and  traced  on  a 
windowpane  or  showcase.  It  will  frequently  be  convenient  to 
reduce  the  mine  maps  by  pantagraph  or  a  slower  method  of  squares. 


MINE    SURVEYS  67 

If  there  is  no  map  available  the  geologist  should  make  a  traverse 
survey  on  a  suitable  scale,  say  50  or  100  feet  to  the  inch.  The 
ordinary  notebook  with  coordinate  ruling,  spaced  ten  lines  to 
the  inch,  is  very  convenient,  and  the  method  will  be  a  modifica- 
tion of  the  notebook  traverse  already  described.  If  there  is  a 
long,  crooked  adit  driven  through  barren  ground  to  the  ore  body 
it  may  not  be  necessary  to  survey  all  of  it,  but  the  survey  should 
then  be  connected  with  the  surface  through  some  air  shaft  or 
other  opening. 

The  Brunton  compass  is  best  adapted  to  underground  work, 
but  the  Gurley  or  any  other  compass  without  a  mirror  may  be 
used.  Satisfactory  results  may  be  had  when  the  compass  is 
held  in  the  hand,  but  a  traverse  plane  table  will  be  found  useful 
in  mines  where  there  are  not  too  many  abandoned  ladders  to 
climb.  It  frequently  happens  that  the  geologist  must  explore 
a  mine  without  an  assistant  or  companion.  In  this  case  he  will 
find  it  convenient  to  save  the  ends  of  his  candles  to  use  as  station 
signals. 

In  making  a  traverse  survey  of  a  mine,  the  geologist  enters 
the  tunnel  or  other  opening  and  paces  as  far  as  he  can  go  and 
still  see  daylight.  He  then  sights  back  to  daylight  and  with 
a  protractor  plots  his  course  in  a  notebook.  He  leaves  a  lighted 
candle  at  this  point  and  then  paces  as  far  as  he  can  go  and  still 
see  the  candle.  The  second  course  is  plotted  in  the  notebook, 
joining  the  course  from  daylight  to  the  first  candle.  This  is 
repeated  until  the  entire  level  is  mapped,  the  stations  being 
placed  wherever  there  is  a  turn  sufficient  to  obscure  the  light 
in  the  portion  already  surveyed.  The  other  levels  are  worked 
out  in  a  similar  manner.  Shafts,  raises,  and  winzes  that  connect 
the  different  levels  should  be  properly  located,  for  by  means  of 
these  the  position  of  the  workings  above  or  below  the  levels 
being  surveyed  is  ascertained.  The  vertical  distance  between  the 
levels  is  obtained  by  counting  the  rounds  of  vertical  ladders  or 
by  sounding  with  a  tape  or  cord.  It  is  difficult  to  represent 
irregular  stopes  with  precise  accuracy,  but  it  is  not  usually 
necessary.  It  is  sometimes  unnecessary  to  map  all  portions  of 
the  mine,  but  the  workings  in  the  vicinity  of  the  ore  bodies 
should  always  be  plotted.  Even  those  who  have  had  long 


68  GENERAL    INSTRUCTIONS 

experience  under  ground  cannot  hold  distances  and  position  in 
the  mind  with  sufficient  accuracy  to  write  a  satisfactory  descrip- 
tion. At  critical  places  greater  accuracy  may  be  desired  and 
a  tape  should  be  used  instead  of  pacing.  When  an  assistant 
is  not  available  the  geologist  should  be  provided  with  a  few  small 
nails  for  securing  one  end  of  the  tape. 

In  the  study  of  contact-metamorphic  deposits  it  frequently 
happens  that  there  is  a  local  attraction  of  the  needle  due  to  the 
presence  of  magnetic  iron.  Under  such  conditions  sufficiently 
accurate  work  may  be  done  with  the  plane  table  and  alidade 
(or  with  the  Gurley  compass,  used  as  an  alidade)  as  follows:  Set 
up  the  plane  table  at  the  portal  of  the  adit  and  orient  it  by  sight- 
ing to  some  known  point;  then  pace  the  adit  as  far  as  possible 
without  losing  sight  of  the  plane  table,  and  at  this  point  place 
a  lighted  candle;  then  go  back  to  the  table,  sight  at  the  candle, 
and  measure  off  the  distance  on  a  suitable  scale;  stick  a  needle 
in  the  board  at  this  point,  which  is  the  location  of  the  candle  on 
the  paper;  also  stick  a  needle  in  the  board  at  the  initial  point, 
which  represents  the  position  of  the  plane  table;  on  the  ground 
mark  the  position  of  the  center  of  the  table  and  remove  it  to 
the  place  where  the  candle  was  stationed.  Place  the  edge  of 
the  alidade  against  the  two  needles  and  orient  the  table  by 
revolving  the  top  until  the  sights  are  in  line  with  the  marker  at 
the  initial  point.  Mark  a  third  station  by  a  candle,  then  sight 
to  and  locate  it.  In  this  manner  the  survey  of  the  level  is  car- 
ried to  its  completion,  the  orientation  being  obtained  by  back- 
sights to  a  candle  at  the  station  last  occupied.  If  the  opening 
is  a  shaft  instead  of  an  adit,  the  positions  of  the  shaft  timbers 
may  be  accurately  located  and  the  connecting  line  used  as  a  base 
line.  If  the  shaft  is  far  out  of  plumb  and  there  is  only  one  open- 
ing, two  weights  may  be  swung  in  the  shaft  and  a  line  connect- 
ing them  used  as  a  base.  These  methods  have  an  additional 
advantage  for  the  geologist  who  is  doing  surface  work  with  the 
plane  table  and  pocket  alidade  and  who  wishes  to  make  an  under- 
ground survey  of  approximate  accuracy  without  a  compass  or 
protractor. 

The  geology  is  plotted  on  the  level  maps  just  as  it  would  be 
on  the  surface,  and  the  vertical  workings  are  studied  as 


MINE    SURVEYS  69 

far  as  possible.  It  is  convenient  to  use  colored  pencils  for  the 
different  formations.  The  ore  which  remains  is  usually  indicated 
by  a  red  color,  filled  in  solid.  Cross  lining  in  the  same  color  is 
used  for  ore  which  has  been  stoped  out.  If  the  value  of  the  ore 
in  different  places  in  the  lode  is  known,  this  also  is  noted  on  the 
map,  with  any  data  concerning  the  character  and  position  of  the 
minerals  which  compose  the  ore.  Every  fissure,  fault,  or  slicken- 
sided  surface  should  be  plotted  on  the  level  map  and  the  angle 
and  direction  of  dip  should  be  noted.  Conspicuous  jointing  or 
bedding  planes  should  also  be  recorded.  As  far  as  possible  all 
the  data  should  be  recorded  on  the  map,  for  this  saves  time 
when  working  on  notes  and  collections.  References,  either  let- 
ters or  numbers,  should  be  used  to  give  the  exact  location  of 
observations  more  fully  recorded  in  the  notebook. 

The  wall  rock  should  be  studied  carefully  and  numerous  speci- 
mens collected.  The  minerals  formed  should  be  noted,  for  it 
often  happens  that  the  chemical  composition  of  the  solutions 
that  deposited  the  ore,  and  the  physical  conditions  under  which 
it  was  deposited,  may  be  ascertained  by  such  study.  For  the 
purpose  of  comparison  it  is  advisable  to  collect  specimens  of  the 
fresh  country  rock  some  distance  away  from  the  lode. 

After  the  level  maps  are  completed,  and  before  the  geologist 
leaves  the  camp  he  should  draw  his  cross  sections  through  the 
mine.  These  should  be  selected  to  show  as  much  as  possible 
of  the  geologic  structure  and  the  relations  of  the  ore  bodies  to 
the  structure.  After  this  has  been  done  it  is  a  useful  practice 
to  summarize  briefly  the  geologic  history  of  the  area,  with  special 
reference  to  the  deposition  of  the  ore.  This  should  be  done 
before  leaving  the  field,  so  that  the  mine  may  be  revisited  if 
necessary.  A  few  hours'  work  in  the  evening,  when  the  mind 
is  on  the  problem  and  the  observations  are  fresh,  may  be  worth 
more  than  a  week's  work  in  the  office.  It  is  not  always  possible 
to  form  definite  conclusions  respecting  the  source  of  the  solutions 
which  deposited  the  ore,  and  this  is  especially  true  for  minor 
occurrences  of  ore  in  a  country  not  extensively  developed.  State- 
ments of  observed  facts  should  be  kept  free  from  speculations 
regarding  the  genesis  of  the  ore,  though  the  evidence  bearing 
on  the  latter  problem  may  be  summarized  in  the  field  with 


70  GENERAL    INSTRUCTIONS 

advantage.  Some  suggestions  are  given  in  connection  with  the 
schedule  on  page  126,  which  may  quicken  the  observation  of  the 
field  geologist  not  familiar  with  this  kind  of  work. 


COLLECTIONS 

Purpose.  In  most  cases  the  geologist  has  two  distinct  pur- 
poses in  the  collection  of  rocks,  fossils,  and  minerals.  The  first 
is  for  making  more  precise  determinations  of  the  character  of 
the  materials  which  the  specimens  represent  than  is  possible  in 
the  field.  These  determinations  may  be  made  by  the  geologist 
himself,  or  the  material  may  be  submitted  to  a  specialist  for 
examination*.  This  purpose  is  wholly  served  with  the  comple- 
tion of  the  report.  The  second  is  to  supply  material  for  per- 
manent exhibit  in  museums  or  for  use  in  teaching.  Both  pur- 
poses should  be  kept  in  mind  while  the  collections  are  being  made. 

Numbering  and  labeling.  The  specimens  of  a  collection 
can  have  no  permanent  value  unless  an  accurate  record  of  locality 
and  important  facts  of  occurrence  is  made  and  connected  with 
the  specimens  by  means  of  numbers  and  labels.  The  expendi- 
ture of  time  and  money  required  to  make  a  collection  and  instal 
it  in  the  office  is  so  great  that  carelessness  or  lack  of  system  tending 
to  impair  the  value  of  the  collection  cannot  be  tolerated.  Every 
collector  is  expected  to  use  some  efficient  system  of  labeling. 

The  specimens  of  each  collection,  pertaining  to  an  excursion, 
a  quadrangle,  a  district,  or  a  given  investigation,  should  be 
numbered  in  one  consecutive  series.  It  is  a  good  plan  to  take 
a  letter  distinctive  of  each  area  and  use  it  as  a  prefix  or  suffix 
to  the  numbers — for  example,  Dl,  2D,  etc.  Different  members 
of  a  party  should  be  assigned  different  sets  of  numbers — for 
example,  A  might  use  1  to  100,  B  101  to  200,  etc.  As  specimens 
and  labels  may  become  separated  by  various  accidents,  it  is  essen- 
tial that  the  number  be  placed  on  the  specimen  when  collected 
or  as  soon  as  possible,  and  also  entered  on  the  map  and  in  notes 
as  elsewhere  provided.  Small  Dennison  pasters  can  be  easily 
carried  in  an  envelope  and  used  when  each  specimen  is  taken. 
If  properly  put  on  they  seldom  crack  off.  By  the  use  of  pen  and 


COLLECTIONS  71 

indelible  ink  more  permanent  figures  can  be  made.  Do  not 
disfigure  specimens  by  unnecessarily  large  pasters  or  numbers. 
Neatness  goes  with  proper  care. 

The  label  should  be  a  precise  statement  of  locality,  collector, 
date,  notebook  reference,  and  perhaps  other  desirable  memoranda. 
It  should  be  comprehensible  to  anyone.  If  symbols  and  abbre- 
viations are  used  in  field  labels,  their  explanation  should  be 
written  out  when  the  collection  is  unpacked  at  the  office.  A 
procedure  which  saves  time  in  the  end  is  to  keep  in  each  note- 
book a  catalogue  of  specimens  so  carefully  worded  as  to  locality 
that  typewritten  labels  can  be  made  directly  from  it. 

A  locality  should  not  be  described  on  a  label  by  reference  to 
places  or  features  not  shown  on  the  topographic  map,  such  as 
a  camp  site,  or  to  the  point  at  which  some  other  specimen  was 
collected;  the  later  information  is,  however,  often  desirable  as 
an  appended  explanatory  memorandum.  Where  there  is  a 
scarcity  of  geographic  names,  it  is  well  to  fix  the  locality  on  the 
label  by  stating  with  reasonable  accuracy  the  distance  and 
direction  from  some  well-defined  point,  as  measured  on  the  map. 

Full  details  of  occurrence  cannot  be  given  on  a  label,  but  sig- 
nificant data  which  can  be  concisely  stated  should  be  added 
when  there  is  room,  for  example,  "From  center  of  dike  15  feet 
wide,"  or  " Upper  contact  zone,  3  inches  wide,  of  large  sill;  see 
No.  —  from  center." 

Collection  of  rocks.  Rock  specimens  which  are  to  be 
retained  in  permanent  collections  should  be  reasonably  uniform 
in  size  and  shape.  They  should  approximate  3  by  4  inches  in 
larger  dimensions,  and  be,  if  possible,  less  than  1  inch  thick. 
In  order  that  material  for  extra  thin  sections  or  for  chemical 
work  may  be  available  for  future  needs,  specimens  should  not 
be  trimmed  too  closely.  Size  and  shape  are  both  subordinate 
to  the  satisfactory  representation  of  rock  characters.  The  skill 
necessary  to  procure  well-shaped  specimens  of  massive  rock  may 
be  acquired  in  a  short  time,  and  should  be  possessed  by  every 
geologist.  Collections  composed  of  too  large  or  too  small,  unsightly, 
and  inconveniently  shaped  specimens  are  justified  only  by  unusual 
field  conditions. 

Specimens  should   present   fresh,   clean  fracture  faces,   as  free 


72  GENERAL    INSTRUCTIONS 

as  possible  from  hammer  bruises,  and  care  should  be  taken  to 
avoid  staining  the  specimen  through  moisture  of  the  hand  or 
in  other  ways. 

Where  there  are  numerous  occurrences  of  a  given  rock  type, 
the  geologist  may  often  wish  to  collect  working  specimens  to 
check  his  field  determinations,  and  these  may  be  of  less  than 
the  regulation  size,  but  care  should  be  taken  that  all  important 
rocks  are  represented  by  full-sized  specimens. 

Museum  specimens  should,  .so  far  as  practicable,  have  the  size 
and  shape  best  suited  to  a  representation  of  the  noteworthy 
features. 

Rock  chips  suitable  for  thin  sections  should  be  inclosed  in 
small  envelopes  provided  for  the  purpose,  and  each  envelope 
should  be  marked  with  the  serial  number  of  the  corresponding 
hand  specimen. 

Requests  for  thin  sections  should  be  restricted  to  the  actual 
needs  of  the  work.  A  small  number  of  carefully  chosen  chips 
may  be  expected  to  yield  more  information  than  several  times 
the  number  taken  at  random,  with  little  thought  of  what  they 
represent. 

It  is  particularly  desirable  that  rocks  submitted  for  quantita- 
tive chemical  analysis  should  be  represented  in  the  collection 
by  abundant  material.  Geologists  are  urged  to  consider  while 
in  the  field  the  possible  need  for  chemical  work,  in  order  that 
the  sample  submitted  for  analysis  may  be  truly  representative 
and  that  there  may  be  on  hand  several  duplicates  of  such  thor- 
oughly investigated  rocks. 

Where  specimens  are  being  collected  for  complete  petrographic 
study  of  an  area,  a  large  number  illustrating  all  phases  of  com- 
position and  texture  will  be  required.  Thus  in  a  transition  zone, 
either  of  primary  origin  or  marking  alteration,  it  is  usually  desir- 
able to  collect  a  suite  of  specimens  illustrating  the  transition. 
Different  numbers  should  be  assigned  to  different  phases.  From 
dikes  specimens  should  be  collected  from  the  center,  the  border, 
and  the  contact  with  inclosing  rocks — as  many  as  are  necessary 
to  show  all  phases  of  texture  present.  From  sills  and  sheets 
there  should  be  specimens  from  the  center  and  both  upper  and 
lower  portions  and  from  the  contact  rocks. 


COLLECTIONS  73 

In  localities  which  illustrate  the  gradual  transition  of  one  rock 
into  another,  series  should  be  collected,  showing  various  stages 
of  the  change  for  chemical  and  microscopic  study. 

Each  hand  specimen  should  be  wrapped  separately,  either  in 
paper  bags  or  in  wrapping  or  newspaper,  so  that  two  or  more 
thicknesses  will  inclose  the  specimen  on  every  side.  Pebbles, 
sand,  earthy  materials,  alteration  products,  etc.,  should  be  col- 
lected in  cloth  or  paper  bags.  After  a  specimen  is  wrapped  it 
is  well  to  place  the  number  on  the  package,  for  convenience  when 
unpacking  the  collection. 

Collection  of  minerals.  The  geologist  should  not  neglect 
opportunities  to  collect  new,  rare,  or  finely  developed  minerals, 
even  if  they  have  no  important  bearing  on  his  work.  If  the 
collecting  involves  much  time,  he  should  obtain  a  few  representa- 
tive specimens,  making  notes  of  occurrence  and  locality,  which 
will  be  useful  to  the  specialist  who  may  wish  to  obtain  further 
material. 

No  general  rule  for  the  size  and  shape  of  mineral  specimens 
can  be  given.  They  should  represent  the  best  development  of 
the  species  found,  their  associations,  and  the  manner  of  occurrence. 
Particular  care  in  packing  mineral  specimens  is  necessary  in 
order  that  the  time  spent  in  collecting  them  may  not  be  wasted. 

Specimens  which  illustrate  the  alteration  of  any  mineral,  per- 
mitting the  study  of  the  process  of  transformation,  are  of  special 
interest,  particularly  if  they  are  pseudomorphs. 

Collection  of  ore  specimens.  In  the  examination  of  a  mine 
or  mining  district  specimens  should  be  collected  to  represent  all 
the  varying  phenomena  of  the  ore  deposits  from  the  points  of 
view  of  mineralogical  composition,  genesis,  and  structural  rela- 
tions. Collections  representing  country  rocks  gathered  during 
the  areal  survey  of  a  mining  district  should  be  made  according 
to  the  rules  already  given  for  rock  collections,  but  the  uniformity 
of  size  there  desired  can  naturally  not  be  expected  to  prevail 
with  regard  to  specimens  of  ore  or  minerals. 

For  a  working  collection  a  full  suite  of  specimens  of  ores,  gangues, 
and  wall  rocks  should  be  obtained,  sufficient  to  furnish  material 
for  a  thorough  microscopic,  chemical,  and  mineralogical  study 
of  the  deposits  under  examination.  In  these  specimens  uniformity 


74  GENERAL    INSTRUCTIONS 

of  size  and  shape  is  not  so  esential,  but  they  should  be  large 
enough  to  show  the  phenomena  or  relations  they  are  designed 
to  illustrate.  When  intended  for  complete  chemical  analysis 
there  should  be  at  least  three  or  four  pounds  of  material.  For 
microscopic  examination  it  is  well  to  break  off,  in  the  field,  thin 
chips  of  appropriate  size  which  will  show  the  phenomena  to  be 
studied. 

For  the  museum  or  reference  collection  type  specimens  should 
be  chosen  which  illustrate  as  clearly  as  possible  the  important 
and  characteristic  phenomena  of  the  deposits,  such  as  the  orig- 
inal condition  of  deposition  and  the  results  of  oxidation  or  altera- 
tion, and  of  secondary  enrichment.  In  preparing  these  specimens 
more  care  should  be  taken  to  approach  uniformity  in  size  and 
shape.  A  size  of  4  by  5  inches  with  a  thickness  of  not  over  2 
inches  is  preferable,  but  larger  specimens  may  be  necessary  to 
illustrate  features  of  mineral  association,  structure,  or  relation  to 
wall  rock. 

For  specimens  illustrating  structure  or  manner  of  deposition 
it  is  important  that  it  should  be  possible  to  orient  their  original 
position  in  the  deposits.  This  may  be  done  by  putting  a  red 
spot  on  the  upper  part  of  the  specimen  and  an  arrow,  in  indelible 
ink,  on  its  side  to  indicate  the  meridian. 

Care  should  always  be  taken  to  avoid  bruising  or  coiling  the 
faces  of  specimens  during  the  collection.  The  specimens  should 
be  numbered  with  indelible  ink  at  the  time  of  collection  and 
should  be  duly  described  by  notes  made  as  soon  thereafter  as 
practicable.  It  is  well  to  assign  a  letter  or  letters  to  a  given 
district  and  to  mark  each  specimen  with  that  letter  and  the 
consecutive  number  as  collected. 

Collection  of  road  materials.  An  important  part  of  the 
study  of  road  materials  is  the  collection  of  samples  for  testing. 

The  samples  should  be  sufficient  in  number  to  represent  fairly 
the  road  materials  of  the  area  surveyed,  including  deposits  having 
not  less  than  200,000  cubic  yards,  and  each  one  should  repre- 
sent the  average  of  the  particular  deposit  sampled.  Each  sample 
should  weigh  not  less  than  30  pounds.  The  pieces,  in  case  of 
rock,  should  pass  through  a  3-inch  and  over  a  IJ-inch  mesh, 
except  one  piece  about  3  by  4  by  6  inches.  They  need  not  be 


COLLECTIONS  75 

wrapped  separately.  If  a  compression  test  is  desired  by  the 
geologist  a  piece  sufficiently  large  to  cut  three  2-inch  cubes  should 
be  included. 

Shipment  should  be  made  in  canvas  or  burlap  bags  by  freight, 
and  all  samples  from  one  locality  should  be  included  in  a  single 
shipment. 

Collection  of  coal  f  rjnples.  In  examining  a  coal  field  for 
the  purpose  of  classifying  the  public  lands  or  of  determining 
the  value  of  the  coal  for  commercial  purposes,  it  is  essential  that 
samples  should  be  procured  for  chemical  analysis.  In  general, 
the  more  important  coal  beds  should  receive  the  most  attention, 
but  it  is  desirable  that  all  coals  having  a  workable  thickness  should 
be  sampled. 

If  the  geologist  is  working  a  field  in  which  there  are  few  or  no 
mines,  it  will  be  necessary  to  procure  samples  from  prospect 
pits  or  natural  exposures,  but  care  should  be  taken  to  avoid 
sampling  weathered  coal,  unless  it  is  impossible  to  obtain  fresh 
material,  and  the  field  is  so  important  and  little  known  that 
even  the  poor  results  to  be  obtained  from  weathered  coal  are 
essential. 

In  every  field  samples  should  be  taken  from  all  the  commercial 
mines,  and  it  is  generally  desirable  to  take  more  than  one  sample 
in  a  mine,  especially  where  there  are  variations  in  the  coal  bed 
as  a  whole,  in  the  various  benches,  or  in  different  beds  worked 
in  the  same  mine.  The  following  rules  in  sampling  mines  have 
been  adopted  by  the  U.  S.  Geological  Survey. 

(a)  Never  accept  weathered  coal,  but  select  a  fresh  face  of 
coal  at  the  point  where  the  sample  is  to  be  obtained,  and  clean 
it  of  all  powder  stains  and  other  impurities. 

(fr)  Spread  a  piece  of  waterproof  cloth  upon  the  floor  so  as  to 
catch  the  particles  of  coal  as  they  are  cut  and  to  keep  out  impuri- 
ties and  excessive  moisture  where  the  floor  is  wet.  Such  a  cloth 
should  be  about  1J  by  2  yards  in  size  and  spread  so  as  to  catch 
all  the  material  cut  down. 

(c)  Cut  a  channel  perpendicularly  across  the  face  of  the  coal 
bed  from  roof  to  floor,  with  the  exceptions  noted  in  paragraph 
(d)  and  of  such  a  size  as  to  yield  at  least  5  pounds  of  coal  per  foot 
of  thickness  of  coal  bed;  that  is,  5  pounds  for  a  bed  1  foot  thick, 


76  GENERAL    INSTRUCTIONS 

10  pounds  for  a  bed  2  feet  thick,  20  pounds  for  a  bed  4  feet  thick, 
etc. 

(d)  Include  in  the  sample  all  material  encountered  in  the  cut, 
except  partings  or  binders  more  than  three-eighths  of  an   inch 
in  thickness  and  lenses  or  concretions  of  sulphur  or  other  impuri- 
ties greater  than  two  inches  in  maximum  diameter  and  one-half 
inch  in  thickness.     Care  should  be  exercised  to  keep  the  groove 
of  uniform  size  throughout  without  regard  to  the  material  encoun- 
tered. 

(e)  If  the  sample  is  wet  take  it  out  of  the  mine  and  dry  it  until 
all   sensible  moisture  has   been   driven   off. 

(/)  If  the  coal  is  not  visibly  moist,  pulverize  and  quarter  it 
down  insicje  the  mine,  to  avoid  changes  in  moisture,  which  take 
place  rapidly  when  fine  coal  is  exposed  to  different  atmospheric 
conditions.  Pulverize  the  coal  until  it  will  pass  through  a  sieve, 
with  one-half  inch  mesh,  and  mix  it  thoroughly  so  that  the  larger 
particles  are  evenly  distributed  throughout  the  mass.  After 
mixing  divide  the  sample  into  quarters  and  reject  opposite  quar- 
ters. Repeat  the  operation  of  mixing  and  quartering  until  a 
sample  of  desired  size  is  obtained.  When  the  work  has  been 
properly  done,  a  quart  sample  is  sufficient  for  chemical  analysis. 
Seal  the  sample  in  either  a  glass  jar  or  a  screw-top  can,  with 
adhesive  tape  over  the  joint. 

(g)  The  analysis  of  such  a  sample  will  show  the  grade  of  coal 
that  may  be  obtained  by  careful  mining  and  picking.  Generally 
the  sulphur  and  ash  in  the  commercial  output  of  the  mine  will 
exceed  the  amount  shown  by  the  analysis,  but  the  commercial 
composition  can  be  approximated  by  multiplying  the  analytical 
results  by  the  empirical  coefficients  1.06  for  sulphur  and  1.29 
for  ash. 

(h)  Accompany  each  sample  by  a  complete  description,  stating 
where  and  how  the  sample  was  obtained  and  what  it  represents. 

(i)  In  publishing  analyses  give  full  descriptions,  as  noted 
above,  together  with  the  name  of  the  collector,  date  of  collection, 
name  of  analyst,  and  treatment  of  sample  after  it  was  collected. 

Stock  sampling.  As  a  rule  mine  sampling  will  be  sufficient  to 
determine  the  quality  of  the  coal,  but  in  certain  cases  it  may 
be  desirable  for  the  geologist  to  sample  stock  piles  or  even  coal 


COLLECTIONS  77 

in  bins  and  railroad  cars.  This  is  extremely  unsatisfactory  and 
no  regulations  can  be  given  which  will  insure  representative 
samples.  If  a  stock  pile  of  several  hundred  tons  is  to  be  sam- 
pled, the  geologist  should  take  at  least  four  large  samples  averaging 
not  less  than  100  pounds  each.  The  sample  should  be  taken 
from  various  points  on  the  stock  pile,  and  care  should  be  exer- 
cised to  include  in  it  the  various  kinds  of  coal  present — that  is, 
lump,  egg,  nut,  slack,  etc.  In  obtaining  these  samples  it  is 
desirable  to  turn  over  as  much  of  the  coal  as  possible,  taking 
an  occasional  shovelful  during  the  process  and  being  careful  to 
include  in  the  part  taken  a  sufficient  number  of  lumps  to  get 
representative  coal.  Each  sample  should  be  pulverized  and 
quartered  down  according  to  the  rules  for  mine  sampling,  and 
either  the  resultant  samples  should  be  sent  to  the  laboratory 
separately  or  the  four  small  samples  should  be  combined,  thor- 
oughly mixed,  and  quartered  down.  In  undertaking  to  sample 
coal  in  railroad  cars  and  bins  the  geologist  will  experience  con- 
siderable difficulty  in  procuring  a  representative  sample,  and  no 
way  so  far  devised  has  succeeded  in  accomplishing  this  purpose. 
It  is  possible,  however,  to  procure  fair  samples  of  a  carload  of 
coal  provided  they  are  taken  as  the  car  is  loaded,  the  sampler 
standing  in  the  car  and  taking  a  shovelful  at  stated  intervals  as 
the  coal  is  being  dumped  into  the  car,  being  careful  to  include 
in  each  sample  all  kinds  of  coal  delivered. 

Labeling.  Sample  cans  for  coal  will  be  furnished  on  request. 
These  cans  will  bear  serial  numbers  on  the  bottoms  by  which 
they  may  be  identified.  The  cans,  when  issued  in  connection 
with  land-classification  surveys,  will  be  charged  against  the 
geologist  ordering  them,  and  the  chief  chemist  of  the  technologic 
branch  will  be  informed  of  the  numbers  issued  to  each  party 
chief.  Blank  forms  for  sending  data  to  the  chemical  laboratory 
should  be  provided  and  also  franked  wrappers  for  inclosing  the 
cans.  These  blanks  will  be  supplied  by  the  technologic  branch. 
Any  can  which  does  not  contain  an  adequate  label  will  be  thrown 
out. 

Samples  for  other  than  chemical  purposes.  In  addition  to 
collecting  samples  for  chemical  analysis,  it  is  desirable  to  have 
in  the  survey  for  purposes  for  exhibition  and  study  a  large  num- 


78  GENERAL    INSTRUCTIONS 

ber  of  coal  samples,  especially  from  the  Western  field,  which 
contains  all  kinds  of  coal  from  lignite  to  anthracite.  Therefore, 
wherever  practicable  samples  should  be  procured  for  this  pur- 
pose. Each  sample  should  be  of  such  size  as  to  fill  two  of  the 
ordinary  sampling  cans,  and  no  fine  coal  should  be  included. 
The  lumps  should  be  carefully  selected  so  as  to  get  representa- 
tive coal,  but  at  the  same  time  so  as  not  to  include  any  foreign 
material  unless  it  is  so  intimately  associated  with  the  coal  as  not 
to  be  separable.  The  cans  containing  these  samples  should  be 
sealed  and  labeled  in  the  same  manner  as  those  containing  samples 
for  chemical  analysis,  and  they  should  be  sent  to  the  office  along 
with  other  collections. 

Collection  Of  fossils.  It  frequently  happens  that  the  con- 
ditions under  which  geologic  work  is  done  render  it  impossible 
for  the  geologist  to  make  full  and  satisfactory  collections  of  fossils. 
In  such  cases,  especially  when  dealing  with  formations  not  gen- 
erally fossiliferous,  a  record  of  the  localities  at  which  fossils  are 
discovered  should  be  made  with  sufficient  care  so  that  they  can 
be  found  subsequently  without  difficulty.  The  record  should 
contain,  in  addition  to  full  topographic  description  and  map 
reference,  a  statement  of  the  lithologic  character  of  the  beds, 
the  character  of  the  fossils — whether  vertebrates,  invertebrates, 
or  plants — their  abundance,  their  state  of  preservation,  and  all 
conditions  affecting  their  collection. 

In  collecting  fossils  there  are  reasons  in  addition  to  those  above 
given  for  gathering  abundant  material.  For  the  purpose  of 
determining  the  exact  geologic  horizon  of  a  bed  it  is  important 
to  have  as  many  species  as  possible  and  to  have  each  species 
represented  by  recognizable  examples.  These  two  ideas  should 
be  in  mind  when  selecting  specimens,  where  transportation 
facilities  are  limited,  as  in  reconnaissance  work.  In  more  detailed 
work,  even  where  the  formations  are  well  known  and  their  limits 
recognized,  full  collections  should  be  made  from  every  fossiliferous 
horizon  of  measured  sections  so  far  as  practicable.  The  data 
thus  obtained  as  to  the  geographic  distribution  and  stratigraphic 
range  of  species  make  future  determinations  and  correlation  of 
horizons  increasingly  more  accurate. 

All  specimens  taken  from  one  bed  in  one  locality,  though  repre- 


COLLECTIONS  79 

senting  many  species,  should  be  given  the  same  number  and  label. 

As  indicated  in  a  previous  section,  great  care  should  be  taken 
in  recording  on  the  map  and  in  the  notebook  the  locality  and 
horizon  where  fossils  are  found.  As  a  rule,  fossils  collected  irom 
different  beds,  even  if  only  a  few  feet  apart,  should  have  dis- 
tinctive labels,  and  specimens  found  on  talus  slopes  or  in  boulders 
should  be  kept  separate  from  those  found  in  place.  When  col- 
lections from  distinct  horizons  are  mixed,  the  fossils  themselves 
will  usually  indicate  that  fact;  but  it  will  often  be  necessary 
to  revisit  the  locality  for  exact  data  as  to  stratigraphy  and  struc- 
ture that  might  have  been  obtained  in  the  first  place  if  the  col- 
lections had  been  more  carefully  made.  Wherever  possible,  a 
sketch  section  should  be  made  in  the  notebook  and  the  exact 
horizons  at  which  fossils  were  collected  should  be  indicated. 

Plants.  In  collecting  fossil  plants  perfect  specimens  should  be 
sought  for;  but  fragments  that  illustrate  essential  or  important 
characters  should  also  be  taken — such  as  the  tip  of  a  leaf,  a  petiole 
with  a  part  of  the  leaf  attached,  a  good,  perfect  base  of  a  leaf, 
or  a  well-preserved  portion  of  the  margin.  By  the  comparison 
of  a  good  series  of  such  fragments,  if  these  are  all  that  can  be 
procured,  a  satisfactory  idea  of  the  form,  size,  and  character  of 
the  leaf  may  usually  be  obtained.  In  collecting  from  Mesozoic 
or  Tertiary  formations  a  fragment  of  bark,  a  leaf  with  no  part 
of  the  margin  preserved,  or  a  mass  of  leaves  without  form  can 
usually  be  discarded  at  once.  Occasionally  it  is  of  course  desir- 
able to  take  anything  in  the  nature  of  plant  remains,  for  a  few 
seemingly  worthless  fragments  obtained  at  a  horizon  where 
plants  are  rarely  found  may  often  be  of  more  interest  than  a 
full  collection  from  a  well-known  locality  or  horizon.  In  any 
case  it  is  desirable  that  the  collector  spend  sufficient  time  to 
insure  a  full  or  at  least  a  fair  representation  of  the  flora  at  each 
locality. 

In  collecting  ferns  the  most  valuable  specimens  are  those  found 
in  fruit,  and  nothing,  no  matter  how  fragmentary,  that  shows 
the  slightest  tendency  to  be  fruit-bearing  should  be  discarded. 
As  ferns  and  conifers  can  usually  be  determined  on  smaller  frag- 
ments than  will  suffice  for  dicotyledons,  such  fragments  need 
not  be  discarded  if  no  better  ones  are  available.  Both  these 


80  GENERAL    INSTRUCTIONS 

classes  of  vegetation  are  valuable  and  should  be  procured  when- 
ever possible.  Fragmentary  impressions  of  stems  and  branches, 
detached  leaves  of  conifers,  lignitized  wood,  etc.,  are  usually  of 
little  diagnostic  value,  and  may  generally  be  rejected,  except 
in  the  case  of  Paleozoic  plants,  when  great  care  should  be  given 
to  the  collection  of  impressions  of  the  outer  bark,  which  is  espe- 
cially essential  to  the  specific  determination  of  such  groups  as 
the  LepidodendreaB  and  Sigillariese. 

When  specimens  are  accidentally  broken  all  the  parts  should 
be  saved  and  kept  together  if  possible.  Counterparts  or  reverse 
impressions  should  be  carefully  preserved  and  also  kept  together. 

Invertebrates.  In  collecting  invertebrate  fossils  it  should  be 
remembered  that  the  important  features  for  their  determination 
are  form,  external  sculpture,  and  internal  structure.  Complete 
specimens  should  therefore  be  obtained  if  possible,  or  if  the  fossils 
are  broken  all  the  pieces  should  be  saved  and  carefully  packed, 
together  with  a  label  indicating  that  they  are  parts  of  one  indi- 
vidual. 

Imperfect  specimens  that  show  internal  structure  or  other 
important  features  should  be  collected  even  if  perfect  examples 
of  the  same  species  are  obtained.  Fossils  preserved  as  internal 
casts  are  often  more  instructive  than  perfect  specimens,  but  in 
such  cases  the  adjacent  matrix  showing  the  imprint  of  the  exterior 
should  also  be  carefully  collected  and  kept  with  with  the  cast  to 
which  it  belongs.  When  fossils  are  distorted  by  pressure  larger 
collections  are  needed  to  assist  in  estimating  the  amount  of  dis- 
tortion and  thus  making  the  determination  more  certain. 

Vertebrates.  In  collecting  vertebrate  fossils  it  is  of  the  greatest 
importance  to  keep  the  bones  of  each  animal  by  themselves, 
separated  from  all  others,  and  to  save  all  the  pieces,  however 
small.  Collect  carefully  all  the  loose  bones  and  fragments  on 
the  surface  or  covered  with  earth,  before  beginning  to  dig  out 
the  skeleton. 

Never  remove  all  the  rock  from  the  skull,  foot,  or  other  delicate 
specimen.  The  more  valuable  the  fossil  the  more  rock  should 
be  left  to  protect  it. 

When  an  entire  foot  is  found,  keep  the  bones  of  each  toe 
together  and  separate  from  the  rest;  then  the  foot  can  be  put 


CHEMICAL    ANALYSES  81 

together  again  with  certainty.  A  complete  foot  is  often  more 
valuable  than  a  skull. 

Get  all  the  bones  of  every  good  specimen,  though  it  may  take 
much  time  to  dig  them  out.  The  absence  of  a  single  toe  bone 
may  greatly  lessen  the  value  of  the  skeleton. 

When  a  rare  bone  cannot  be  got  out  of  the  rock  entire,  it  is 
important  to  measure  its  exact  length  on  a  piece  of  thick  paper, 
and  pack  this,  properly  marked,  with  the  pieces  saved.  A  draw- 
ing of  such  a  bone,  however  rude,  may  prove  of  value. 

Small  specimens  are  often  more  valuable  than  larger  ones,  and 
should  be  carefully  sought  for  when  a  good  locality  is  found. 
Single  bones,  if  one  end  is  perfect,  are  worth  saving.  If  freshly 
broken,  careful  search  should  be  made  for  all  the  pieces. 

Every  fossil  or  fragment  should  be  wrapped  separately  in 
paper,  sufficient  soft  paper  being  used  to  prevent  all  danger  of 
injury  by  rubbing.  Cotton  should  be  used  in  packing  fragile 
specimens.  Each  lot  that  should  be  kept  together,  as  the  fossils 
from  one  locality  or  the  parts  of  an  individual,  should  be  put  in 
a  sack,  or  securely  wrapped  in  strong  manila  paper,  with  a  label 
inside  and  a  tag  or  number  outside. 

Packing.  Specimens  of  all  kinds  should  be  packed  in  small 
boxes  so  that  they  can  be  handled  by  one  man.  Each  box  should 
be  entirely  full,  all  interstices  being  filled  with  soft  paper,  excelsior, 
hay,  or  similar  material,  but  not  with  sawdust.  The  top  of  the 
box  should  be  plain  and  the  directions  marked  with  paint  or  ink. 
Each  box  should  be  bound  with  wire  or  otherwise  strengthened. 


CHEMICAL  ANALYSES 

All  requests  for  chemical  analyses  should  be  accompanied  by 
full  information  as  to  the  locality  from  which  the  material  comes, 
the  nature  of  the  geologic  problem  involved,  and  the  bearing  of 
the  analysis  requested  on  its  solution. 

In  the  case  of  petrographic  specimens,  microscopic  study  of 
thin  sections  and  a  careful  comparison  of  the  rock  with  speci- 
mens in  the*  petrographic  reference  collection  already  analyzed 
should  precede  chemical  analysis.  A  brief  statement  of  the 


82  GENERAL    INSTRUCTIONS 

results  of  such  microscopic  study  should  accompany  the  request, 
in  order  that  the  chemist  may  be  informed  of  the  presence  of 
unusual  constituents  or  of  the  abundance  of  others  ordinarily 
present  in  small  quantity. 

When  waters  are  forwarded  for  analysis  the  entire  material 
must  be  collected  through  filters  in  clean  glass  bottles  or  carboys 
at  one  time,  so  that  the  entire  specimen,  measuring  not  less  than 
two  gallons,  may  be  thoroughly  uniform,  and  these  vessels  must 
be  properly  sealed  with  paraffin.  Whenever  it  is  practicable, 
geologists  desiring  analyses  of  water  should  inform  the  chief 
chemist  of  the  general  character  of  the  water  and  receive  detailed 
instructions  as  to  collecting  and  bottling.  Ordinary  druggist's 
filter  paper  is  not  suitable  for  the  collection  of  acid  waters. 

The  nature  of  the  analysis  desired  should  be  stated,  the  ele- 
ments to  be  determined  being  given  whenever  a  partial  analysis 
only  is  called  for.  The  term  " complete  analysis"  is  understood 
to  mean  the  determination  of  all  the  elements  which  occur  com- 
monly in  rocks,  including  titanium,  phosphorus,  barium,  strontium, 
lithium,  etc. 

If  analyses  of  this  or  similar  material  from  the  same  region  have 
been  already  printed,  the  fact  should  be  stated,  with  references. 

The  name  of  the  substance  to  be  analyzed  should  be  given,  and 
the  locality  should  be  stated  on  the  label  accompanying  the 
sample,  as  well  as  in  the  office  letter  of  request. 


GEOLOGIC  NOMENCLATURE 

The  advantages  of  uniformity  in  the  nomenclature  of  any 
science  are  so  manifest  that  they  must  appeal  strongly  to  every 
one.  The  need  of  agreement  in  geologic  nomenclature  is  espe- 
cially urgent  by  reason  of  the  tendency  to  excessive  multiplica- 
tion of  stratigraphic  names  with  the  resulting  confusion  and 
burden  on  the  memory.  In  order  to  correct  this  tendency  in  so 
far  as  publications  of  the  U.  S.  Geological  Survey  are  concerned, 
a  certain  procedure  has  been  adopted  by  the  survey  in  the  treat- 
ment of  matters  relating  to  nomenclature.  This  procedure  is 
embodied  in  the  following  instructions. 


GEOLOGIC    NOMENCLATURE  83 

"  Rules  of  nomenclature  and  classification  have  been  adopted 
for  the  Geologic  Atlas  of  the  United  States,  and  published  in 
the  Twenty-fourth  Annual  Report.  Every  person  doing  geologic 
work  in  the  survey  should  become  thoroughly  familiar  with  these 
rules.  The  cartographic  unit  is  the  formation.  Aggregates  of 
formations  are  designated,  in  ascending  order,  groups,  series,  and 
systems,  and  parts  of  formations  are  members.  These  terms, 
when  coupled  with  a  geographic  name,  forming  a  title,  should  be 
used  only  in  the  accepted  sense,  and  not  loosely  or  indefinitely. 

"The  following  systems  and  series  are  recognized: 

System.  Series. 

T ' (pSocene. 

f  Pliocene. 
Tertiary I  Miocene. 

|  Oligocene. 

Cretaceous.  I  Eocene. 

Jurassic. 
Triassic. 

f  Permian. 
Carboniferous |  Pennsylvanian. 

I  Mississippian. 
Devonian. 
Silurian. 
Ordovician. 

f  Saratogan. 
Cambrian <  Acadian. 

I  Georgian. 
Algonkian. 
Archean. 

"Certa'n  rules  in  regard  to  the  definition  and  application  of 
geologic  formation  names,  based  on  principles  of  priority  and 
established  usage,  have  been  adopted  by  the  survey.  A  com- 
mittee on  geologic  names  has  been  appointed  to  interpret  these 
rules,  and  geologists  and  paleontologists  must  transmit,  con- 
siderably in  advance  of  the  presentation  of  manuscript,  a  list 
of  the  names  they  intend  to  use  for  all  stratigraphic  divisions. 
Moreover,  as  it  is  necessary  to  obtain  the  committee's  approval 
not  only  of  the  new  names,  but  of  the  particular  application  of 
every  geologic  name  to  be  used  in  the  text  or  on  the  illustrations, 
even  those  to  which  only  a  casual  reference  is  made,  the  manu- 
script itself  must,  when  completed,  be  sent  to  the  committee 


84  GENERAL    INSTRUCTIONS 

for  examination.  This  must  be  done  before  the  paper  is  trans- 
mitted for  publication,  and  the  author  must  procure  from  the 
committee  a  letter  containing  a  list  of  the  names  used  and  indi- 
cating the  action  taken  thereon,  to  be  transmitted  with  the 
manuscript.  This  regulation  applies  both  to  manuscripts  for 
survey  publications  and  to  those  that  are  to  be  published  else- 
where, either  by  other  Government  Bureaus,  by  State  surveys 
with  which  cooperation  is  being  carried  on,  or  in  proceedings  of 
societies  or  scientific  journals.  In  the  case  of  such  outside  pub- 
lication, it  is  especially  important  that  the  manuscripts  should 
be  referred  to  the  committee,  as  such  manuscripts  do  not  pass 
through  the  hands  of  the  survey  editor.  The  committee  will 
give  full  consideration  to  the  views  and  wishes  of  the  author, 
but  its  approval  of  all  geologic  names,  both  old  and  new,  is 
essential." 

It  is  generally  impossible  to  decide  on  the  stratigraphic  sub- 
divisions or  their  correlation  until  the  survey  of  a  district  is  well 
advanced  or  is  entirely  completed,  and  some  office  work  done. 
Tentative  field  names  or  other  designations  should  therefore  be 
employed  and  long-distance  correlations  avoided  until  the  strati- 
graphic  units  have  been  traced  to  or  otherwise  identified  with 
formations  already  defined.  Such  field  names  can  easily  be 
replaced  when  final  correlations  have  been  made,  and  no  prejudice 
is  incurred  in  favor  of  an  incorrect  correlation. 


PERMISSION  TO  PUBLISH 

Control  of  publication  of  material  obtained  at  the  expense  or 
under  the  auspices  of  an  official  survey  should  be  exercised  by 
the  official  head  of  the  survey,  and  publication  should  be  made 
only  with  express  permission.  Formal  regulations  to  this  effect 
are  in  force  in  most  surveys.  The  following  is  the  regulation 
in  the  U.  S.  Geological  Survey. 

"  Papers  based  in  whole  or  in  part  on  material  procured  or 
observations  made  in  connection  with  official  survey  work  may 
be  published  elsewhere  than  in  the  Survey  series  only  on  the 
written  permission  of  the  director.  Requests  for  permission  to 


PERMISSION    TO   PUBLISH  85 

publish  must  be  accompanied  with  the  complete  manuscripts. 
The  permission  will  not  be  granted  until  the  terms  proposed  to 
be  used  have  been  approved  by  the  committee  on  geologic  names. 
"This  rule  is  not  intended  to  hamper  in  any  degree  the  free 
expression  of  'scientific  opinion  or  the  widest  dissemination  of 
conclusions,  but  it  is  intended  (a)  to  prevent  premature  pub- 
lication of  results  properly  belonging  in  official  reports,  (fr)  to 
prevent  acrimonious  or  personal  controversy  on  scientific  matters, 
and  (c)  to  prevent  inconsistent  and  conflicting  usage  in  matters 
of  nomenclature  and  classification/' 


PART   II 
INSTRUCTIONS  FOR  SPECIAL  INVESTIGATIONS 

PURPOSE  OF  SCHEDULES 

THE  following  schedules  have  been  prepared  with  a  view  to 
securing  system  and  completeness  in  making  and  recording 
observations.  Most  of  them  are  not  intended  to  be  exhaustive 
or  to  cover  all  possible  points  on  which  the  specialist  will  make 
observations.  They  are  rather  for  the  guidance  and  help  of  the 
specialist  when  he  is  working  outside  his  specialty.  Thus  the 
glacialist  or  paleontologist  will  have  occasion  at  times  to  make 
observations  on  mineral  deposits  which  are  being  mined  or 
quarried,  and  the  appropriate  schedules  will  indicate  to  him  what 
points  are  of  most  importance  and  should  be  most  carefully 
rioted.  In  like  manner  the  economic  geologist  or  petrographer 
might  be  at  a  loss  to  know  what  particular  features  should  be 
observed  in  a  deposit  of  glacial  material.  In  short,  the  need 
for  the  schedules  arises  from  the  extent  to  which  specialization 
is  necessarily  carried  in  geologic  work,  and  they  are  designed  to 
overcome  some  of  the  disadvantages  arising  from  this  special- 
ization. 

In  the  field  study  of  economic  mineral  deposits,  the  geologist 
should  bear  in  mind  that  his  results,  to  have  their  greatest  value, 
must  be  based  on  a  thorough  knowledge  of  the  geologic  relations 
of  the  deposits.  If  he  does  not  obtain  this  knowledge  his  work 
will  be  a  more  or  less  complete  failure,  no  matter  how  many  facts 
he  may  ascertain  regarding  the  deposits  themselves.  If  time 
for  the  study  of  a  deposit  is  limited  a  considerable  share  should 
be  devoted  to  the  general  geology  of  the  district  in  which  it  occurs 
— to  its  geologic  and  physiographic  history — although  these 

86 


INTERPRETATION  OF  LAND  FORMS  87 

matters  may,  to  the  superficial  observer,  appear  to  have  little 
if  any  bearing  on  the  subject  under  investigation.  The  schedules 
naturally  call  special  attention  to  facts  to  be  observed  regarding 
deposits  of  the  particular  class  to  which  they  relate,  but  it  is  to 
be  understood  that  in  every  case  a  knowledge  of  the  general 
geology  of  the  district  is  to  be  acquired  as  a  foundation  for  the 
special  inquiries  tabulated  in  the  schedules. 

It  has  seemed  desirable  to  preface  the  schedules  with  a  some- 
what fuller  statement  of  some  of  the  special  points  to  be  observed 
than  the  tabular  form  permits.  Material  assistance  has  been 
rendered  in  the  preparation,  both  of  these  introductory  state- 
ments and  of  the  schedules,  by  Messrs.  Whitman  Cross,  Arthur 
Keith,  G.  H.  Ashley,  W.  H.  Emmons,  A.  H.  Brooks,  P.  S.  Smith, 
A.  C.  Spencer,  and  W.  C.  Alden. 


DESCRIPTION  AND  INTERPRETATION  OF  LAND  FORMS 

In  deciphering  the  past  history  of  a  region  the  geologist  is  aided 
by  an  understanding  of  the  character  and  origin  of  the  surface 
forms.  Thus  a  marine  cut  bench  on  a  hillside  means  relative 
uplift  of  the  land,  or  a  peneplain  means  a  long  period  of  relative 
stability.  The  value  of  this  evidence  comes  from  the  fact  that 
forms  are  the  result  of  certain  processes  acting  on  certain  struc- 
tures. So,  if  a  particular  type  of  land  surface  is  observed  the 
geologist  may  deduce  the  processes  that  have  been  effective,  or 
the  history  or  genesis  of  the  area.  As  such  deductions  constitute 
the  main  use  of  this  kind  of  evidence  from  the  standpoint  of  the 
geologist,  those  points  which  serve  this  end  should  be  particularly 
sought. 

The  description  and  interpretation  of  land  forms  can  no  more 
be  treated  adequately  by  long-range  views  alone  than  can  strati- 
graphy. It  is  desirable  to  gain  first  a  broad  view  of  the  region, 
then  to  study  the  features  in  detail,  and  then  to  assemble  the 
facts  collected  by  these  two  methods  of  observation.  Such 
study  should  consist  of  both  office  and  field  work,  neither  alone 
giving  the  best  results,  although  the  latter  is  far  more  important 
than  the  former. 


88    INSTRUCTIONS    FOR    SPECIAL    INVESTIGATIONS 

Office  study  should  precede  and  also  follow  the  field  work,  but 
as  the  compilation  of  the  results  differs  but  slightly  from  the 
method  pursued  in  other  sciences,  it  need  not  be  discussed  in 
,  detail  here.  The  aim  of  modern  science  is  to  make  use  of  time 
most  effectively.  Therefore,  when  any  work  may  be  done  equally 
well  by  two  methods,  the  shorter  one  is  to  be  chosen.  Much 
time  may  be  saved  by  a  study  of  maps  and  the  literature  before 
visiting  a  region.  In  this  study  the  relation  of  the  particular 
area  to  the  larger  land  forms  outside  of  it  should  be  noted,  as 
well  as  the  main  features  within  its  limits.  In  this  preliminary 
study  any  peculiar  features  which  will  require  particular  atten- 
tion in  the  field,  such  as  abrupt  termination  of  ridges  or  sudden 
changes  in  the  direction  of  the  streams,  should  be  noticed.  The 
general  arrangement  of  the  various  topographic  units  should 
be  grasped,  and  so  far  as  possible,  a  plan  of  campaign  laid  out. 
As  much  information  concerning  the  geologic  structure,  climate, 
etc.,  as  is  possible  should  be  gained,  but  the  attempt  should  not 
be  made  to  do  those  things  which  can  be  better  done  by  obser- 
vation in  the  field. 

Subdivision  of  land  forms  may  be  carried  to  any  degree  of 
refinement  desired.  In  the  accompanying  schedule  (No.  1) 
three  types — plains,  plateaus,  and  mountains — are  adopted,  and 
it  is  believed  that  all  areas  which  are  encountered  by  the  field 
geologist  will  belong  to  one  or  more  of  these  types.  Each  of 
these  divisions  may  be  treated  as  consisting  of  three  parts:  the 
upland,  the  valleys,  and  the  intervalley  areas,  or  spurs.  Each 
of  these  details  should  be  considered,  first  separately,  and  then 
in  its  relation  to  the  others.  When  this  has  been  done,  the 
observer  will  be  in  a  position  to  undertake  the  statement  of  the 
origin  of  the  present  form.  The  character  of  the  previous  form, 
of  which  the  present  form  is  a  derivative,  next  requires  attention. 
It  may  be  best  deciphered  by  one  alert  to  the  forms  character- 
istic of  each  agent  of  land  sculpture.  Thus,  if  a  peneplain  is 
suggested,  evidence  of  old  age  should  be  sought  in  the  character 
of  the  drainage,  deep  rock  weathering,  absence  of  ledges,  absence 
of  undrained  areas,  monadnocks,  lack  of  interruption  of  pene- 
plain surface  on  rocks  of  very  different  resistance,  etc.  If  these 
conditions  are  not  fulfilled,  their  absence  must  be  explained,  or 


INTERPRETATION  OF  LAND  FORMS  89 

the  interpretation  is  erroneous.  After  a  hypothesis  is  formulated, 
it  should  be  tested  by  some  new  line  of  study,  for  every  hypo- 
thesis must  at  least  fit  the  known  facts,  but  its  probability  is 
increased  in  proportion  as  it  explains  some  previously  unexpected 
facts.  For  instance,  the  theory  of  continental  glaciation  was 
first  advanced  to  account  for  scattered  boulders  of  foreign  mate- 
rial which  showed  scratched  surfaces.  When  this  theory  was 
tested  by  inquiring  the  effect  of  such  a  hypothetical  ice  sheet  on 
the  drainage,  and  was  found  to  explain  perfectly  such  conditions 
as  those  in  the  region  around  the  Great  Lakes,  it  commanded 
greater  credence. 

While  much  of  the  theoretical  consideration  of  the  data  required 
can  be  profitably  worked  out  after  returning  to  the  office,  it  is 
of  prime  importance  that  the  greater  part  should  be  done  in 
the  field  with  the  forms  before  the  observer,  for  in  that  way 
suggestions  may  be  tested  and  critical  localities  visited.  If, 
however,  the  time  for  field  work  is  limited,  enough  information 
for  a  general  description  may  often  be  afforded  by  photographs. 
In  taking  pictures  it  is  important  to  note  the  compass  direction 
in  which  the  camera  is  pointed.  Furthermore,  if  possible,  at  least 
two  views,  at  right  angles  to  each  other,  of  all  important  features 
should  be  obtained.  Notebook  sketches  are  of  great  value, 
especially  in  supplementing  photographs,  but  the  personal  inter- 
pretation should  not  obscure  the  facts,  for  it  may  be  necessary 
to  modify  early  opinions  in  the  light  of  further  knowledge. 

In  the  use  of  the  accompanying  schedule,  which  is  primarily 
intended  for  field  observation,  it  should  be  remembered  that 
often  only  a  few  of  the  points  necessary  for  a  complete  descrip- 
tion may  be  found  in  a  single  view,  and  therefore  answers  to 
every  one  of  the  headings  indicated  on  the  schedule  are  not 
expected.  The  object  of  the  study  should  be  kept  firmly  in  mind 
and  emphasis  placed  on  those  portions  which  further  the  main 
object  of  the  party.  The  observer  should  be  alert  for  corrobora- 
tive evidence  that  can  be  obtained  from  all  the  branches  of  geology, 
as,  for  instance,  stratigraphy,  petrology,  etc. 


90    INSTRUCTIONS   FOR    SPECIAL   INVESTIGATIONS 


PETROLOGIC  OBSERVATIONS 

Rocks  are  the  documents  that  contain  a  large  part  of  the 
geologic  record.  To  read  that  record  is  the  geologist's  duty, 
and  it  will  not  do  to  jump  at  the  sense  by  catching  a  word  here 
and  there. 

Rock  masses  represent  primarily  the  result  of  certain  pro- 
cesses, acting  on  certain  materials,  under  certain  conditions. 
Petrology  is  the  broad  science  of  rocks,  dealing  with  the  product 
and  from  a  study  of  its  characters  and  relations  reaching  con- 
clusions as  to  these  processes,  materials,  and  conditions.  These 
processes  include  metamorphism  and  decay  of  rocks,  the  latter 
being  but  an  initial  process  in  the  forming  of  still  other 
rocks. 

For  the  geologic  interpretation  of  rocks  the  primary  requisite 
is  a  knowledge  of  the  rock  itself.  In  proportion  as  its  characters 
and  relations  are  known  its  significance  as  a  geologic  mass  is 
understood.  It  is,  then,  manifestly  a  primary  duty  of  the  field 
geologist  to  study  carefully  in  the  field  the  rocks  which  come 
under  his  observation  and  to  provide  adequate  material  for 
refined  examination  in  the  office  or  laboratory.  It  is  important 
for  him  to  realize  that  the  more  fully  the  character  of  a  rock 
is  appreciated  in  the  field  the  more  helpful  are  its  hints  in  direct-, 
ing  the  course  of  investigation. 

Some  of  the  important  things  to  observe  in  connection  with 
different  classes  of  rocks  will  be  briefly  mentioned  here. 


IGNEOUS  ROCKS 

Rocks  representing  fused  material  from  unknown  sources  in 
the  earth's  interior  are  seemingly  primary.  If  derived  from 
older  rocks  only  the  general  chemical  nature  of  these  original 
rocks  can  be  inferred.  The  igneous  rocks  are  of  great 
importance  as  telling  almost  all  that  we  know  of  the  earth's 


IGNEOUS    ROCKS  91 

interior  and  illustrating  many  principles  of  chemistry  and 
physics. 

Character  of  the  rock.  Observe  mineral  composition  and 
texture  carefully;  the  proper  classification,  description,  and 
naming  of  a  rock  depend  on  these  factors.  Note  variation  of 
either  composition  or  texture  in  a  given  mass;  both  require 
explanation.  Heterogeneity  in  composition  is  often  difficult  to 
explain.  Is  it  related  to  form  of  mass  or  to  contact  zones,  or  is 
it  irregular  in  distribution?  Is  the  transition  from  one  phase 
to  another  sudden  or  gradual? 

Changes  in  texture  indicate  conditions  of  consolidation.  Dense 
or  glassy  contact  zones  with  coarser  interior  show  the  chilling 
effect  of  cold  wall  rock,  water,  or  the  atmosphere.  An  even, 
granular  texture  in  contact  zones  speaks  for  highly  heated  coun- 
try rock,  produced  perhaps  by  the  passage  of  much  magma 
through  a  conduit,  or  a  great  depth  of  the  mass  at  the  time  of 
consolidation.  Fluidal  textures  in  contact  zones  imply  move- 
ment just  before  consolidation. 

Mode  of  occurrence.  Observe  form,  size,  and  position  of 
intrusive  masses  with  relation  to  character  of  the  rocks,  with 
reference  to  the  history  of  the  region,  and  for  data  bearing  on 
the  question  of  the  mechanics  of  igneous  intrusion.  Do  the 
contact  zones  of  intrusive  masses,  either  with  wall  rock  or  included 
fragments,  show  evidence  of  fusion  of  wall  rock  or  inclusion  and 
assimilation  of  melted  material,  or  is  the  contact  sharply  mechan- 
ical? If  large  fragments  are  included  in  an  intrusive  rock  see 
if  their  source  can  be  determined.  Specimens  illustrating  these 
relations  are  necessary. 

Relations  of  rocks.  Where  several  igneous  rocks  occur  in 
association,  observe  relations  of  occurrence  and  evidences  of 
relative  age  of  different  kinds.  If  one  cuts  another  ascertain 
which  is  the  older.  Contact  modifications  in  the  younger  rock 
are  common.  The  sequence  of  eruptions  is  often  interesting  as 
bearing  on  magmatic  differentiation  and  the  succession  of  events 
at  a  volcanic  center. 

In  many  places  small  masses  or  dikes  are  characteristically 
associated  with  certain  large  bodies.  Note  such  restrictions  of 


92    INSTRUCTIONS    FOR    SPECIAL    INVESTIGATIONS 

occurrence  and  represent  different  dikes  liberally  by  speci- 
mens. 

Effusive  rocks.  The  petrographic  character,  features  of 
association,  and  succession  are  matters  of  prime  interest  in  con- 
nection with  effusive  as  well  as  with  intrusive  rocks.  It  is  impor- 
tant to  determine  the  location  of  the  vent  from  which  a  lava 
has  issued  and  its  connection  with  or  seeming  independence  of 
a  center  of  typical  volcanic  action.  If  a  volcano  is  indicated 
problems  arise  as  to  the  nature  of  the  eruptions,  whether  effusions 
of  lava  or  explosive  outbursts,  the  period  of  activity,  and  the 
extent  and  state  of  preservation.  In  the  case  of  ancient  volcanoes 
which  have  been  greatly  eroded  the  phenomena  may  become 
largely  those  of  intrusive  rocks. 

Observe  carefully  the  extent  and  thickness  of  lava  flows  and 
the  features  of  their  upper  and  lower  zones  and  of  the  surface. 
These  points  bear  on  the  liquidity  or  viscosity  of  the  magma  as 
it  issues  from  the  vent.  The  more  liquid  lavas  flow  readily  and 
cover  a  larger  space  than  those  that  are  viscous,  some  of  which 
build  up  domelike  hills  above  their  vents. 

Metamorphism.  Always  study  with  care  the  change  pro- 
duced in  a  country  rock  or  an  included  fragment  by  an  igneous 
magma  or  associated  solutions.  Ascertain  the  original  character 
of  the  wall  rock  and  the  extent  of  its  metamorphism,  as  shown 
by  gradation  from  maximum  to  minimum  effect,  the  latter  being 
commonly  related  to  distance  from  the  intrusive  body.  Note 
the  character  of  the  secondary  minerals  when  possible  and  illus- 
trate by  specimens. 

Decomposition.  The  destruction  of  an  igneous  rock  is  usually 
accomplished  by  deep-seated  chemical  action  or  by  the  domi- 
nantly  mechanical  processes  of  weathering  near  or  at  the  surface. 
In  the  former  case  the  special  characters  of  a  given  rock  may 
be  changed  by  the  work  of  circulating  waters.  Certain  com- 
ponents may  be  removed  and  others  brought  in.  Thus  rocks 
of  different  primary  character  may  be  brought  to  resemble  each 
other  and  even  the  distinctive  properties  of  an  igneous  mass 
may  disappear,  as  in  extreme  silicification  or  kaolinization. 
Such  alteration  is  usually  so  localized  that  the  geologist  may 


IGNEOUS    ROCKS  93 

observe  various  stages,  even  perhaps  to  the  fresh  rock,  and  by 
obtaining  suitable  specimens  afford  means  for  an  interesting 
study.  Consider  especially  the  relation  of  such  decomposition 
to  ore  deposition. 

Study  the  surface  decay  of  rocks  with  relation  to  the  process  of 
weathering,  the  formation  of  soil,  the  mechanical  destruction  of  the 
exposed  mass,  and  the  deposition  of  detritus. 

Pyroclastic  rocks.  Intermediate  between  massive  igneous 
and  sedimentary  rocks  in  some  respects  are  the  pyroclastic 
rocks.  They  may  represent  debris  from  volcanic  explosions 
which  has  fallen  on  the  slopes  of  the  volcano  or  at  no  great  dis- 
tance and  has  suffered  no  transportation.  Contemporaneous, 
and  perhaps  intermingled  with  such  deposits,  may  be  others 
that  have  been  washed,  by  heavy  rains  attendant  on  eruption, 
to  varying  distances  down  the  slopes  or  into  bodies  of  water. 
After  eruption  ceases  volcanic  debris  is  naturally  transported 
and  deposited  at  more  or  less  remote  points  in  normal  sedi- 
ments. 

Make  observations  to  determine  the  relations  of  pyroclastic 
deposits  to  their  source  both  in  space  and  time.  Sediments 
composed  of  volcanic  material  transported,  sorted,  and  deposited 
under  usual  conditions  exhibit  the  characteristics  of  clastic 
rocks  referred  to  below.  As  a  rule  those  which  belong  essentially 
to  the  volcano  exhibit  structural  relations  to  the  volcanic  center, 
association  with  lava  streams,  irregular  mingling  of  coarse  and 
fine  particles,  crude  bedding,  and  petrographic  uniformity  as 
to  constituents.  The  finer  particles  are  sharply  angular,  many 
of  the  larger  ones  are  somewhat  rounded,  and  bombs  are  of 
common  occurrence. 

Collect  specimens  wherever  desirable,  following  the  instructions 
in  this  handbook  in  regard  to  form,  number,  label,  and  record. 


94    INSTRUCTIONS   FOR    SPECIAL    INVESTIGATIONS 

Summary.     The  following  statement  summarizes  the  observa- 
tions to  be  made  on  igneous  rocks: 


Observations. 


Significance. 


1.  Megascopic  character  of  rock  as  to 

(a)  composition,  (6)  texture,  (c) 
uniformity  or  variability  in  mass, 
(d)  relations  of  all  characters  to 
features  of  occurrence,  (e)  speci- 
mens. 

2.  Mode  of  occurrence-batholith,  stock, 

dike,  sill,  laccolith,  flow,  tuff,  brec- 
cia, or  agglomerate. 

3.  As  to  method  of  intrusion:    (a)  Are 

contacts  sharply  defined?  (6)  ex- 
amine wall  rock  or  inclusion  for 
evidence  of  fusion  and  assimila- 
tion ;  (c)  search  for  source  of  large 
inclusions. 

4.  Relations  of  rocks  of  a  series  as  to 

occurrence,  age,  and  mass. 

5.  Character  and  extent  of  contact  met- 

amorphism,  associated  ore  depos- 
its, and  attendant  alteration  of 
country  rock. 

6.  Seek  source  of  a  lava  flow  and  its  as- 

sociation with  other  flows  or  with 
pyroclastic  material.  In  case  of  a 
series  study  sequence  and  struc- 
tural relations. 

7.  Pyroclastics: 

(a)  Chaotic  arrangement,  or  rude 
bedding,  angular  form  of  smaller 
particles,  association  with  lavas, 
dip  from  a  center. 

(6)  Rounded  particles,  distinct 
bedding,  admixture  of  nonvol- 
canic  matter,  fossils. 

(c)  Bombs  or  glassy  droplike  par- 
ticles in  deposit. 


1.  The  excellence  of  petrographic  classi- 

fication, description,  and  nomen- 
clature depend  on  the  thorough- 
ness of  these  field  observations, 
which  may  also  bear  on  the  causes 
of  textural  or  mineral  differences 
of  rocks  and  many  other  problems. 

2.  Physical  features  of  origin,  historical 

connections,  and  meaning  of  many 
characters  of  rocks. 

3.  Contribute  to  determination  of  the 

methods  by  which  batholiths, 
stocks,  etc.,  come  to  place  Opin- 
ions differ. 


4.  Bear  on  history   of  eruptions   and 

magmatic  differentiation. 

5.  Character  of  magma  as  to  its 

ciated  gases  and  solutions. 


6.  Associated  lavas  indicate  a  volcanic 

center  whose  history  should  be  de- 
ciphered if  possible;  the  extent, 
nature  of  eruptions,  and  degree  of 
dissection. 

7.  (a)    Characters    indicate    that   beds 

are  directly  of  volcanic  origin, 
have  suffered  little  transporta- 
tion, and  may  represent  part  of 
old  volcano. 

(6)  Transportation  and  deposition 
under  conditions  common  to  or- 
dinary elastics. 

(c)  Derived  from  explosion  of 
liquid  lava. 


SEDIMENTARY    ROCK&-CLASTIC    ROCKS  95 


SEDIMENTARY  ROCKS 

Much  of  the  history  of  the  earth's  surface  in  past  ages  is  recorded 
in  the  sedimentary  rocks.  The  geologist's  interest  in  them  is 
many-sided.  Beyond  and  above  the  purely  petrographic  interest 
lies  the  consideration  of  the  sediments  as  geologic  units  to  be 
interpreted  in  their  bearing  on  earth  history.  Primarily  this 
is  a  question  of  the  rocks  as  deposits. 

The  clastic  sediments  tell  of  older  rocks  destroyed,  of  detritus 
transported  by  various  agencies,  and  of  deposition  under  many 
differing  conditions.  Such  deposits  must,  then,  be  studied  for 
the  light  they  throw  on  the  conditions  and  events  of  the  epoch 
they  represent. 

The  sedimentary  rocks  other  than  elastics  are  chiefly  precipi- 
tates from  solution  and  their  most  evident  importance  is  in 
connection  with  the  place  and  conditions  of  deposition.  Most 
of  these  rocks  owe  their  origin  to  the  action  of  organisms,  directly 
or  indirectly,  or  to  the  desiccation  of  isolated  bodies  of  water. 

It  is  manifestly  impossible  to  give  here  more  than  a  suggestive 
outline  of  necessary  observations  concerning  features  of  sedi- 
mentary rocks,  with  hints  as  to  their  significance. 


CLASTIC  ROCKS 

Petrographic  character.  Comparatively  little  attention  has 
been  paid  by  petrographers  to  the  inherent  properties  of  clastic 
rocks.  The  meager  terminology  is  evidence  of  this  neglect. 
The  difficulty  of  interpreting  the  conditions  under  which  sedi- 
ments were  deposited  is  no  doubt  due  in  part  to  imperfect  knowl- 
edge of  the  character  of  the  sediments  themselves;  hence  closer 
study  of  the  rocks  is  highly  desirable  for  the  advancement  of 
both  petrography  and  stratigraphic  geology.  The  nature  of 
the  rock  particles  in  a  sediment  should  be  determined  sufficiently 
to  permit  the  use  of  appropriate  names  and  descriptive  terms 
and  to  lead  to  the  recognition  of  peculiar  or  characteristic  feat- 
ures of  formations  under  investigation.  " Sandstone"  is  too  often 


96    INSTRUCTIONS   FOR    SPECIAL    INVESTIGATIONS 

used  as  a  sufficiently  exact  lithologic  term.  It  is  important  to 
know  whether  the  sand  grains  are  quartz,  feldspar,  calcite,  vol- 
canic ash,  or  other  materials  of  peculiar  character.  "  Conglom- 
erates" are  often  described  with  no  mention  of  the  character 
of  pebbles  or  of  the  usual  sandy  matrix.  Such  deficient  descrip- 
tion is  usually  due  to  deficient  observation. 

Source  Of  materials.  The  mineral  and  rock  particles  of 
sediments  should  be  examined  with  care  for  their  evidence  as 
to  the  character  of  existing  land  masses  of  a  given  epoch.  By 
this  evidence  an  important  stratigraphic  break  may  be  detected 
in  an  apparently  conformable  series  of  beds — a  break  corre- 
sponding to  overlap  in  some  districts.  The  pebbles  of  conglom- 
erates and  the  particles  of  the  coarser  grits  and  sandstones  will 
often  yield  this  information  on  megascopic  study,  but  specimens 
for  office  examination  should  be  taken.  The  microscope  may 
show  that  a  certain  sandstone  is  derived  largely  from  quartzite 
and  not  from  granite  or  other  igneous  or  metamorphic  rocks. 

The  site  of  land  areas  furnishing  debris  is  in  some  places  indi- 
cated by  increasing  coarseness  of  conglomerates  in  the  direction 
of  their  source  or  by  restricted  distribution  of  certain  components. 

Transportation  and  deposition.  Rock  detritus  may  now  be 
seen  in  all  stages  of  transportation  from  sources  far  inland  to 
the  sea,  and  much  is  known  of  submarine  deposits.  Wind,  ice, 
and  water  are  visible  agents  of  transportation.  Presumably 
some  ancient  clastic  deposits  represent  nearly  every  stage  of 
each  process  of  transportation.  The  recognition  of  the  stage 
or  process  must  be  the  ultimate  aim  of  the  geologist. 

Most  wind-blown  material  is  in  the  end  transported  and  deposited 
by  water,  but  glacial  de*bris  representing  till  or  moraine  may  be 
preserved  as  such,  with  slight  modification.  Recent  studies  of 
certain  ancient  conglomerates  have  led  to  the  belief  that  they 
represent  till.  The  subangular  form  and  striated  faces  of  pebbles 
and  the  irregular  texture  of  the  matrix,  showing  no  evidence  of 
sorting  by  water,  constitute  the  decisive  criteria  in  this  case. 

Sediments  formed  above  sea  level  are  grouped  as  continental. 
They  clearly  include  lacustrine,  river,  and  land  deposits  and 
the  question  of  their  importance  relative  to  marine  beds  among 
the  ancient  formations  is  one  of  the  chief  problems  of  modern 


CLASTIC    ROCKS  97 

stratigraphy — a  problem  which  the  geologist  should  have  con- 
stantly in  mind.  Studies  of  nonfossiliferous  marine  and  conti- 
nental clastic  rocks  of  similar  textures,  tending  to  determine 
critical  differences  between  them,  are  much  needed.  The  various 
phenomena  of  nearly  all  kinds  of  sediments  must  be  studied 
together  and  finally  interpreted  in  the  light  supplied  by  the 
association  of  characters. 

Attention  has  been  particularly  called  to  certain  features  of 
clastic  sediments  in  illustration  of  the  preceding  remarks,  but 
it  must  be  realized  that  characters  not  here  referred  to  may  be 
of  great  importance  in  special  cases. 

Fossils.  Fossils  should  be  sought  with  great  care  in  all  deposits, 
not  only  for  their  chronologic  significance  but  also  for  the  evi- 
dence they  furnish  as  to  conditions  of  sedimentation.  Many 
marine  and  fresh- water  beds  are  distinguishable  only  in  this  way. 
Remains  of  land  animals,  especially  of  dismembered  vertebrates, 
may  exhibit  marks  of  abrasion,  suggesting  the  fluviatile  character 
of  the  sediments  containing  them.  It  may  be  that  fragments 
of  fossil  wood  or  bone  have  been  derived  from  older  strata — a 
possibility  to  be  kept  in  mind. 

Character  of  particles.  The  size  and  form  of  the  particles 
in  a  sediment  are  often  highly  significant.  Large  size  and  angu- 
lar form  indicate  that  fragments  have  not  suffered  transportation 
to  a  great  distance  from  their  source.  Small  and  rounded  sand 
grains  have  presumably  traveled  far  or  suffered  attrition  by 
wave  or  wind  action.  Fine  mud  is  not  necessarily  the  product  of 
extreme  transportation.  It  may  result  from  erosion  of  fine-grained 
deposits  near  at  hand  or  from  wind  erosion  in  an  arid  region. 

Homogeneity  of  deposits  is  a  factor  of  various  aspects.  It 
may  indicate  a  near-by  source  of  material — a  land  mass  mainly 
of  limestone  or  quartzite  or  some  other  prevalent  rock — or  it 
may  tell  of  volcanic  outburst,  as  in  the  case  of  a  tuff.  On  the 
other  hand,  there  is  a  textural  homogeneity  produced  by  long- 
continued  sorting  by  water,  in  which  size,  specific  gravity,  or 
hardness  of  minerals  sorted  is  usually  the  controlling  factor. 
This  is  illustrated  by  a  quart zose  sandstone. 

Heterogeneity  in  character  of  clastic  components  may  testify 
to  the  destruction  of  a  complex  land  mass;  or,  if  the  rock  is 


98    INSTRUCTIONS    FOR    SPECIAL    INVESTIGATIONS 

a  mixture  of  certain  minerals  in  notably  uniform  proportion,  as  in 
some  arkose  grits,  a  granitic  or  gneissic  source  may  be  inferred. 

Texture.  The  uniformity  or  variability  in  texture  of  sediments 
should  be  carefully  noted.  A  stratum  possessing  uniformity 
over  a  great  area  implies  uniform  conditions  in  that  area;  the 
vertical  extent  of  such  strata  tells  of  continuance  of  conditions 
in  time.  Such  uniformity  is  most  common  in  subaqueous  sedi- 
ments but  is  also  shown  by  some  fluviatile  and  basin  deposits. 

Variability  in  texture  is  indicative  of  restricted  or  rapidly 
changing  conditions,  such  as  those  of  most  continental  and  some 
offshore  marine  deposits. 

Bedding.  The  bedding  of  sediments  is  of  much  significance. 
Where  bedding  planes  are  closely  spaced,  notably  even,  and 
laterally  persistent,  they  tell  of  quiet  waters  and  slow  accumu- 
lation of  material;  where  they  are  far  apart  they  show  rapid 
accumulation,  commonly  in  turbulent  waters.  Cross-bedding  is 
indicative  of  wave  action  or  great  river  currents  and  must  be 
studied  in  the  light  of  other  characters  of  the  strata. 

Color.  The  color  of  strata  is  of  extremely  variable  importance. 
Observation  should  determine  whether  a  given  color  is  character- 
istic of  a  formation,  is  restricted  locally  within  it,  or  transgresses 
formation  limits.  The  cause  of  its  color  and  whether  this  is  of 
primary  or  secondary  origin  must  be  determined,  and  these 
problems  usually  require  office  study.  The  color  may  pertain 
to  the  clastic  particles,  to  the  cementing  substance,  or  to  a  pig- 
ment of  later  origin  than  the  deposit. 

The  red  color  common  to  many  formations  is  of  particular 
interest.  It  is  often  considered  diagnostic  of  the  basin  deposits 
of  arid  regions  or  of  material  derived  from  such  areas.  The 
usual  absence  of  fossils  in  red  beds  and  the  ferruginous  nature 
of  the  pigment  are  points  in  favor  of  a  climatic  significance  for  red 
strata.  But  certain  red  deposits  are  plainly  derived  from  older  red 
rocks  and  hence  generalizations  must  be  based  on  close  observation. 

Markings.  Various  markings  made  on  the  surfaces  of  mud 
deposits  before  they  were  covered  and  preserved  by  succeeding 
layers  are  of  notable  value  in  showing  certain  conditions  of  depo- 
sition. Mud  cracks,  raindrop  pits,  organic  trail  marks,  footprints, 
etc.,  testify  to  exposed  mud  flats.  These  need  not  be  of  tidal 


CHEMICAL   AND    ORGANIC    SEDIMENTS  99 

origin,  as  is  sometimes  assumed,  but  characterize  as  well  the 
flood  plains  of  rivers,  marginal  plains  about  lakes,  and  the  interior 
basin  deposits  of  temporary  lakes,  especially  in  desert  regions. 
Ripple  marks  and  allied  forms  belong  chiefly  to  the  littoral  zone 
of  lacustral  or  marine  beds,  or  to  fluviatile  deposits. 

Cement.  The  cementing  material  of  many  clastic  rocks  is  a 
strikingly  characteristic  feature.  It  may  have  been  formed  at 
the  time  of  deposition,  as  in  calcareous  sandstones  and  marls 
laid  down  in  sea  water  rich  in  lime.  It  may  have  been  gradually 
deposited  from  waters  circulating  through  the  porous  rock  long 
after  its  formation,  and  although  such  cementation  is  a  change 
in  the  character  of  the  sediment  it  is  not  commonly  included 
under  metamorphism.  The  induration  of  a  clastic  rock  may, 
however,  date  from  some  period  of  intense  chemical  activity, 
and  thus  be  classed  as  metamorphic  change. 

It  is  evidently  desirable  to  investigate  the  induration  of  sedi- 
mentary rocks  and  determine  the  nature  of  the  cement  and,  if 
possible,  the  time  of  its  deposition.  Lack  of  cement  may  signify 
that  the  sediment  has  never  been  saturated  by  waters  capable 
of  depositing  a  binding  substance  or  that  solvent  waters  have 
abstracted  the  former  cement. 

CHEMICAL  AND  ORGANIC  SEDIMENTS 

Chemical  precipitates  and  rocks  consisting  of  organic  remains 
are  simple  of  interpretation  as  compared  with  clastic  rocks,  but 
tell  little  beyond  the  conditions  of  their  deposition. 

Limestone  is  the  most  important  sediment  of  chemical  origin. 
As  it  is  in  many  cases  produced  by  the  aid,  directly  or  indirectly, 
of  organisms,  fossils  are  apt  to  be  present  and  should  be  dili- 
gently sought.  Marine  and  fresh-water  limestones  are  thus  to 
be  distinguished.  The  name  limestone  is  often  indiscriminately 
applied  to  carbonate  rocks  regardless  of  the  amount  of  mag- 
nesium and  iron  carbonate  that  may  be  present.  Material  for 
investigation  of  composition  should  be  collected,  and  it  may  be 
desirable  to  carry  a  small  bottle  of  hydrochloric  acid  to  discrimi- 
nate magnesian  limestone.  It  is  important  to  note  the  character 
of  impurities  in  limestones — their  texture,  fracture,  bedding,  and 
color.  The  cause  of  characteristic  colors  should  be  determined. 


100  INSTRUCTIONS    FOR    SPECIAL    INVESTIGATIONS 


Gypsum  and  salt  deposits,  even  if  not  of  industrial  importance, 
are  significant  of  lagoons  or  of  isolated  seas,  and  usually  testify 
to  arid  climatic  conditions,  which  may  also  often  be  inferred 
for  associated  clastic  sediments. 

The  now  recognized  continental  character  of  carbonaceous 
deposits  derived  from  land  plants  sheds  also  much  light  on  the 
nature  of  associated  rocks. 

Summary.  A  summarized  statement  of  the  observations  to 
be  made  on  sedimentary  rocks  is  subjoined. 


Observation. 


Significance. 


1.  Accurate  determination  of  character 

of  constituent  particles,  character 
of  cement,  and  texture. 

2.  Search    for    particles    derived    from 

older  rocks  of  recognizable  charac- 
ter, particularly  pebbles  and  larger 
particles. 

3.  Study  general  character,  extent,  and 

associations  of  rocks  as  forming 
geologic  units. 

4.  Search  for  and  collect  fossils. 

5.  Special  characters: 

(a)  Large  and  angular  fragments. 

(fe)  Small,  rounded  grains. 

(c)  Homogeneity  of  stratum. 

(d)  Heterogeneity  of  stratum. 

(e)  Great  variability  of  characters. 

(/)  Bedding;  spacing  of  distinct 
planes,  extent  (lateral  or  ver- 
tical) of  uniform  character. 

(0)  Cross-bedding. 

(h)  Color;  does  it  belong  to  frag- 
ments, cement,  or  secondary 
pigment. 

(t)  Mud  cracks,  raindrop  pits,  or- 
ganic trail  markings,  foot- 
prints. 

0')  Cement  material;  its  character 
and  amount;  is  it  primary  or 
secondary? 


1.  Basis  for  petrographic  treatment  and 

deductions  as  to  history  of  rock. 

2.  Show  character  of  land  masses  ex- 

posed.    May  demonstrate  strati- 
graphic  break. 

3.  Bear  on  methods  of  transportation 

and  conditions  of  deposition. 

4.  Age  and  condition  of  deposition. 
5. 

(a)   Proximity  to  source;    probable 

continental  deposit. 
(6)  Transportation  and  sorting. 

(c)  Character  of  source  or  degree  of 

sorting. 

(d)  Complex  source  or  possibly  fluvi- 

atile  deposit. 

(e)  Common  in  fluviatile  and  offshore 

deposits. 

(/)  Continuity  of  conditions  areally 
or  in  time. 

(gr)  Wave  action  (subaqueous)  or 
current  (fluviatile). 

(h)  May  indicate  source  of  de'bris,  or 
constitute  a  diagnostic  feature 
as  to  conditions  of  time  of  de- 
position. 

(i)  Indicate  exposed  mud  flats,  tidal, 
flood  plain,  or  lake  margin, 
or  interior  basin. 

(/)  May  have  diagnostic  value  in  rec- 
ognition of  bed,  or  denote 
change  long  after  deposition. 


METAMORPHIC    ROCKS  101 


METAMORPHIC  ROCKS 

General  observations.  Igneous  and  sedimentary  rocks  alike 
are  subject  to  change  by  many  different  angencies  operating 
under  various  conditions  and  subject  to  recurrence  at  distinct 
periods.  The  changes  vary  in  degree,  ranging  from  a  barely 
perceptible  alteration  to  the  total  obliteration  of  the  primary 
characters.  In  the  introductory  text  of  the  geologic  folios  meta- 
morphic  rocks  are  defined  to  include  those  in  which  "the  newly 
acquired  characteristics  are  more  pronounced  than  the  old  ones." 
It  goes  without  saying,  however,  that  all  degree  of  metamorphism 
should  be  studied  with  care.  Important  studies  both  of  weather- 
ing and  of  deep-seated  metamorphism  require  an  appreciation 
of  the  problems  while  in  the  field  and  an  intelligent  selection  of 
material  for  detailed  examination  in  the  office. 

The  observer  must  remember  that  metamorphic  rocks  have  a 
threefold  interest.  First,  the  rocks  themselves  are  notable 
because  many  of  their  acquired  characters,  both  of  mineral 
composition  and  texture,  are  peculiar  to  them.  Second,  they 
represent  igneous  or  sedimentary  masses,  and  recognition  of  their 
original  nature  leads  to  information  concerning  epochs  preced- 
ing the  metamorphism.  Third,  the  processes  by  which  the 
metamorphism  has  been  accomplished  are  important  from  the 
physical  and  chemical  as  well  as  from  the  historical  standpoint. 

Painstaking  observation  of  megascopic  characters  is,  if  any- 
thing, more  necessary  than  in  unaltered  rocks.  Compared  with 
igneous  rocks  the  crystalline  schists  exhibit  marked  variations 
in  composition  and  texture  within  a  given  geologic  mass,  and 
study  of  these  features  may  furnish  important  lines  of  evidence. 
By  discriminating  phases  of  rocks  varying  degrees  of  meta- 
morphism may  often  be  recognized,  and  where  several  stages  are 
known  both  the  nature  of  the  original  materials  and  the  pro- 
cesses of  alteration  may  be  worked  out.  All  stages  must  be  repre- 
sented by  specimens  for  detailed  study. 

Different  rocks  acted  on  by  the  same  agents  differ  greatly  in 
their  susceptibility  to  change.  Thus  shales  become  slates,  giving 


102  INSTRUCTIONS    FOR   SPECIAL    INVESTIGATIONS 

evidence  mainly  of  mechanical  changes  and  often  but  slightly 
of  chemical  changes,  whereas  feldspathic  sandstones  and  impure 
limestones  are  readily  altered  to  highly  crystalline  schists.  Con- 
glomerates or  porphyritic  igneous  rocks  often  form  the  basis  for 
layered  schists,  and  some  fissile  hornblende  schists  are  traceable 
into  diabase  or  diorite. 

In  areas  that  have  suffered  regional  metamorphism  it  some- 
times happens  that  no  trace  of  primary  minerals  or  textures 
can  be  recognized  and  even  larger  structural  features  are  greatly 
obscured.  In  such  areas  rocks  rich  in  quartz  or  in  calcite  may 
furnish  clues  to  the  determination  of  the  original  sediments.  Lay- 
ering in  schists  and  gneisses  may  or  may  not  represent  stratification. 

In  areas  of  contact  metamorphism  it  is  usually  possible  to 
determine  the  course  of  alteration  by  studying  the  progressive 
change  in  passing  away  from  the  intrusive  mass. 

In  studying  all  phases  of  metamorphism  it  is  of  the  greatest 
importance  to  determine  if  materials  have  been  added  or  sub- 
tracted, one  or  both,  or  if  only  the  substances  of  the  original 
rock  appear  in  the  metamorphic  product. 

Metamorphism  of  all  sorts  may  be  attended  by  the  segregation 
of  metallic  minerals  and  the  formation  of  workable  ores. 

Summary.  The  following  points,  therefore,  are  of  prime 
importance  in  the  study  of  metamorphic  rocks: 

(a)  Determine  the  large  features  and  structural  relations  of  the 
original  rocks  considered  as  formations. 

(b)  In  all  classes  of  metamorphic  rocks  seek  the  most  and  least 
altered  phases;    estimate  the  nature  of  change  from   one  to  the 
other. 

(c)  Study  all  phases  of  alteration  in  order  to  establish  a  pro- 
gressive series.     Even   if  incomplete  such  a  series  may  indicate 
the  processes  of  alteration. 

(d)  Distinguish    mere    mechanical    metamorphism    from    mole- 
cular and  chemical  change. 


OBSERVATIONS  IN  STRUCTURAL  GEOLOGY  103 


OBSERVATIONS  IN  STRUCTURAL  GEOLOGY 

The  facts  of  geologic  structure  should  be  gathered  for  three 
purposes : 

(a)  For  use  in  determining  the  thickness  and  sequence  of  for- 
mations and  in  directing  observations  in  the  field. 

(6)  For  controlling  the  drafting  of  maps  and  sections. 

(c)  For  deciphering  the  history  of  the  earth. 

For  immediate  field  purposes.  It  is  obvious  that  dip  and 
strike  should  be  observed  in  order  to  calculate  the  thickness  and 
sequence  of  the  rocks.  Once  those  factors  are  determined  they 
can  be  used  to  detect  other  structures,  like  faults  and  duplications 
that  may  be  locally  obscured. 

Metamorphic  products  also  must  be  observed  in  order  to  trace 
and  correlate  formations  which  were  originally  the  same  but  now 
are  locally  changed. 

An  early  understanding  of  the  faults  and  folds  of  a  region  is 
essential  to  mapping  and  guides  the  geologist  to  critical  locali- 
ties. So,  too,  it  is  of  the  utmost  importance  in  the  study  of 
economic  deposits,  some  of  which,  like  coal,  oil,  and  gas,  are  more 
or  less  available  according  to  their  position  in  the  folded  and 
faulted  strata.  Metalliferous  deposits  may  follow  the  contact  of 
two  formations,  lie  in  certain  fissures,  follow  fault  planes,  or  fill 
the  lower  part  of  the  synclines,  and  to  mine  them  best  an  inti- 
mate knowledge  of  the  structure  is  needed.  A  knowledge  of  the 
relation  between  deposits  and  structure  will  lead  to  the  dis- 
covery of  new  and  unsuspected  deposits. 

For  drafting  purposes.  In  the  drafting  of  maps  a  knowledge 
of  the  dip  of  strata  along  the  formation  boundaries  is  essential 
in  order  to  show  properly  the  curving  boundary  lines  produced 
by  various  topographic  forms.  These  variations  are  of  small 
consequence  where  the  dips  are  over  60°,  but  are  of  radical  impor- 
tance if  the  dips  are  20°  or  less. 

In  drafting  structure  sections  a  knowledge  of  the  dips  of  the 
strata  will  frequently  determine  the  presence  of  a  fault,  where 
in  the  body  of  a  formation  there  are  no  visible  offsets  or  disloca- 
tions. It  seems  hardly  necessary  to  state  that  the  dips  should 


104  INSTRUCTIONS    FOR   SPECIAL    INVESTIGATIONS 

be  recorded  in  the  field  as  well  as  seen,  but  there  is  a  common 
tendency  to  omit  them  from  the  record.  A  proper  procedure 
is  to  put  into  the  notes  the  dip  and  strike  of  every  rock  about 
which  any  comment  is  made.  This  suggestion  applies  to  dips 
of  cleaveage  and  schistosity  as  well  as  to  those  of  stratification. 

For  historical  purposes.  Most  of  the  facts  that  are  noted 
in  regard  to  rocks  record  their  environment — the  conditions  which 
led  up  to  their  production.  Still  other  events,  those  that  fol- 
lowed the  formation  of  the  rocks,  can  be  deciphered  from  their 
structure.  In  the  sedimentary  and  igneous  records  there  are 
many  gaps.  These  are  bridged,  in  part,  by  the  facts  of  structure. 

One  series  of  rocks  may  rest  across  the  beveled  edges  of  an 
older  series,  thus  showing  that  the  earlier  rocks  were  uplifted, 
worn  away,  and  depressed  again  by  further  movement  before 
the  later  rocks  were  deposited.  The  pressures  may  have  been 
great  enough  to  fold  or  break  the  older  rocks,  or  even  to  alter 
their  minerals,  while  similar  facts  may  not  be  shown  in  the 
second  series.  These  are  signs  of  the  greater  earth  events  ard 
from  them  the  geologist  infers  that  the  time  between  the  series 
was  of  great  duration. 

Some  large  areas  are  characterized  by  faults  of  normal  type. 
It  may  be  concluded  from  this  fact  that  the  thin  layer  now 
visible  has  been  deformed  without  horizontal  compression  and 
has  merely  accommodated  itself  to  the  disturbed  underbody  of 
the  earth. 

Other  great  districts  exhibit  rocks  folded  in  troughs  and  arches, 
or  piled  over  each  other  on  faults.  Such  facts  clearly  indicate 
that  the  visible  part  of  the  earth's  crust  has  been  enormously 
compressed  and  shortened  horizontally. 

Still  another  region  may  contain  rocks  whose  textures  and 
minerals  are  more  or  less  altered  from  their  original  condition. 
These  phenomena  show  clearly  that  either  the  pressures  pro- 
ducing them  or  the  load  of  overlying  rocks  were  at  their  maximum 
and  entirely  overcame  the  strength  of  the  metamorphosed  beds. 

Thus,  in  one  part  of  the  country  or  another,  rocks  are  now 
exposed  at  the  surface  which  slowly  came  up  to  it  from  greater 
or  less  depths.  They  contain  records — fragmentary,  it  is  true — 
of  the  conditions  through  which  they  passed  at  different  levels. 


GLACIERS    AND    GLACIAL    DEPOSITS  105 

A  gabbro,  for  instance,  may  have  been  intruded  into  other 
rocks  at  a  very  great  depth.  Dynamic  movements  at  some 
later  time  combined  with  the  weight  of  overlying  rocks  to  trans- 
form this  rock  into  a  hornblende  schist  or  gneiss.  In  different 
parts  of  its  mass  both  altered  and  unaltered  phases  may  still 
be  found.  By  erosion  the  mass  approaches  the  surface  and  lies 
in  succession  in  the  zones  of  flowage,  of  fracture,  and  of  weather- 
ing. -Evidences  of  processes  in  all  these  zones  may  be  found 
in  the  rock — close-knit  crystalline  minerals  for  the  first;  joints 
and  dislocations  more  or  less  filled  by  later  minerals  for  the 
second;  and  gradual  expansion,  disintegration,  and  hydration  for 
the  third.  During  this  rise  to  the  surface  the  rock  may  have 
been  affected  by  a  second  compression,  and  the  structures  pro- 
duced by  this  process  will  be  seen  modifying  those  of  the 
first. 

In  brief,  it  can  be  seen  that  the  record  of  structural  geology 
begins  where  that  of  sedimentation  or  intrusion  ends,  and  that 
each  is  a  necessary  complement  to  the  other.  Concurrent  with 
and  modifying  each  were  the  processes  of  erosion.  These  fur- 
nish a  record  of  still  broader  and  simpler  dynamic  movements 
— those  of  uplift,  depression,  and  warping.  Some  large  districts 
are  marked  by  an  almost  entire  absence  of  geologic  structures. 
In  them  the  geologist's  insight  into  the  past  is  sadly  limited. 


GLACIERS  AND  GLACIAL  DEPOSITS 

Existing  mountain  glaciers.  It  is  of  importance  to  note 
the  phenomena  of  existing  glaciers,  both  because  of  their  own 
interest  and  because  of  their  value  as  indicating  general  atmos- 
pheric and  climatic  conditions  and  also  as  affording  a  means  of 
interpreting  the  mode  of  action  of  ancient  mountain  and  conti- 
nental glaciers  and  the  part  played  by  them  in  the  history  of 
the  earth. 

Observations  should  be  made  wherever  possible  on  methods 
of  erosion,  derivation  of  the  drift,  transportation,  and  deposition. 

Note  should  be  made  of  indications  as  to  whether  the  ice  is 
stationary;  advancing  and  crowding  on  moraines  and  bordering 


106  INSTRUCTIONS    FOR    SPECIAL    INVESTIGATIONS 

terraces;  encroaching  on  lakes,  marshes,  or  forests;  discharging 
icebergs  to  the  sea;  or  retreating  from  its  moraines. 

Earlier  mountain  glaciation.  It  is  of  importance  to  ascer- 
tain the  conditions  prevailing  in  mountain  districts  during  Pleis- 
tocene time  and  to  develope  means  of  correlating  glacial  phe- 
nomena of  the  mountains  and  of  the  plains  with  non-glacial 
phenomena,  such  as  those  due  to  lacustrine,  fluvial,  and  marine 
agencies  of  the  same  time. 

In  some  places  earlier  prevalent  conditions  were  so  different 
from  those  of  the  present  that  glaciers  occupied  valleys  and 
slopes  which  are  not  now  glaciated,  and  many  of  these  earlier 
glaciers  extended  to  lower  altitudes,  some  of  them  reaching 
the  seacoast  or  lacustrine  basins  in  such  a  manner  as  to  afford 
means  of  determining  the  time  relations  of  the  glaciation  and 
the  submergence. 

Wherever  possible  observations  should  be  made  on  the  deposits 
of  earlier  and  more  extensive  glaciers,  and  these  should  be  dis- 
criminated carefully  from  non-glacial  deposits.  For  example,  in 
examining  the  high-level  gravels  of  the  mountain  districts  and 
similar  deposits  look  for  faceted  and  striated  pebbles  and  boul- 
ders, lack  of  assortment,  and  stratification  by  water,  and  the 
presence  of  erratics  too  large  for  water  transportation;  note 
the  maximum  size  of  stones  and  their  topographic  situation;  look 
for  glaciated  rock  surfaces  near  or  beneath  the  deposits. 

Pleistocene  continental  glaciation.  In  the  study  of  Pleis- 
tocene glacial  phenomena  it  has  been  determined  that  the  epoch 
did  not  consist  simply  of  the  development,  extension,  and  melt- 
ing of  a  single  continental  ice  sheet,  but  that,  on  the  contrary, 
there  were  successive  stages  of  glaciation,  each  marked  by  the 
development,  extension,  and  final  melting  of  an  ice  sheet;  that 
these  glaciers  deployed  from  more  than  one  center  and  differed 
considerably  in  extent  and  in  the  directions  of  their  movement; 
that  the  stages  of  glaciation  alternated  with  stages  of  deglacia- 
tion,  when  such  climatic  changes  occurred  as  resulted  in  the 
melting  of  the  ice  sheets,  the  development  of  new  soils,  and  the 
introduction  of  new  faunas  and  floras.  During  these  stages  of 
glaciation  and  deglaciation  a  great  variety  of  phenomena  were 
developed  as  a  consequence  of  variations  in  the  extent  of  the 


GLACIERS   AND    GLACIAL   DEPOSITS  107 

different  advances  and  retreats  of  the  ice  fronts  and  in  the  methods 
and  amounts  of  erosion,  transportation,  and  deposition.  The 
character  of  a  large  part  of  the  northern  half  of  North  America, 
and  its  adaptability  to  human  habitation  or  at  least  to  the  carry- 
ing on  of  particular  pursuits,  are  in  large  measure  a  consequence 
of  these  geologic  processes. 

Much  of  the  science  of  glaciology  is  still  in  a  formative  stage; 
for  instance,  the  number  of  the  glacial  and  interglacial  stages, 
their  relative  length,  the  character  of  the  attendant  climatic 
changes,  the  attitude  and  altitude  of  the  different  parts  of  the 
continent,  the  relation  of  glacial  phenomena  to  non-glacial  phe- 
nomena south  of  the  drift  limit,  and  many  minor  phenomena 
are  not  yet  satisfactorily  demonstrated,  nor  are  the  causes  of 
Pleistocene  glaciation  yet  so  well  understood  as  not  to  need 
the  development  of  new  hypotheses.  It  is  therefore  of  impor- 
tance that  a  large  amount  of  detailed  data  based  on  careful 
observation  be  accumulated,  not  only  as  the  means  of  inter-1 
preting  the  geology  of  particular  areas  but  for  the  development 
of  the  science  itself.  From  the  nature  of  the  case,  dependent 
as  continental  glaciation  was  on  the  climate  and  geography  over 
wide  areas,  it  is  necessary  that  the  study  of  the  phenomena  be 
carried  on  throughout  areas  of  great  extent  and  under  widely 
varying  conditions,  and  observations  should  be  made  wherever 
possible.  For  instance,  in  determining  the  age  of  a  particular 
glacial  deposit  it  is  impossible,  merely  by  collecting  and  identi- 
fying fossils  to  refer  the  deposit  to  its  proper  horizon.  If  the 
stratigraphic  relation  cannot  be  traced  directly,  the  geologist 
is  dependent  on  the  observation  and  correlation  of  a  large  mass 
of  data  concerning  the  composition  of  the  deposit,  derivation 
of  material,  direction  of  ice  movement,  degree  of  decomposition 
by  weathering,  maturity  of  development  of  the  drainage  systems 
thereon,  and  other  phenomena  in  order  to  form  a  reliable  opinion 
concerning  its  age. 

As  a  basis  for  the  glacial  study  it  is  essential  to  have  some 
knowledge  of  the  general  geology,  the  constitution  and  attitude 
of  the  different  rock  formations,  and  their  relation  to  the  topog- 
raphy of  the  bed-rock  surface,  both  in  the  area  to  be  studied 
and  in  the  region  traversed  by  the  ice  hi  reaching  this  area.  The 


108  INSTRUCTIONS    FOR    SPECIAL    INVESTIGATIONS 

action  of  the  ice  in  deploying,  in  eroding,  and  in  forming  the  sev- 
eral classes  of  its  deposits  depended  largely  on  the  configuration 
of  the  bed-rock  surface  overridden  by  it.  For  a  knowledge  of 
the  character  of  this  surface  beneath  the  drift  a  study  should 
be  made  of  the  streams  with  reference  to  their  continued  occu- 
pancy of,  or  diversion  from,  their  preglacial  courses.  For  this 
purpose  the  character,  locations,  and  dimensions  of  rock  gorges, 
falls,  and  rapids  should  be  examined  with  reference  to  the  broader 
parts  of  the  valleys  that  are  now  wholly  or  in  part  filled  with 
drift.  Records  of  wells  and  other  drillings  afford  the  means  of 
tracing  these  buried  watercourses.  The  study  of  the  relations 
and  dimensions  of  the  earlier  and  later  watercourses  and  the 
presence  of  glacial  drift,  loess,  and  lacustrine  or  other  deposits 
in  them  may  afford  measures  of  the  time  elapsing  before,  between, 
or  since  two  or  more  successive  ice  invasions. 

The  composition  of  the  drift  in  various  parts  of  an  area  depends 
on  the  character  of  the  rock  formations  overridden,  so  that  the 
two  should  be  studied  together.  The  presence,  as  constituents 
of  the  drift,  of  rocks  not  otherwise  known  to  occur  in  the  region 
(such  as  the  occurrence  of  diamonds  in  the  drift  of  the  Mississippi 
Valley)  may  also  give  clues  as  to  their  character  and  locations. 
Rough  analyses  of  the  lithologic  composition  of  the  drift  may 
readily  be  made  by  taking  indiscriminately  from  a  section  of 
drift  one  to  several  hundred  pebbles  and  sorting  according  to 
their  character.  In  doing  this,  however,  note  should  be  taken 
as  to  the  contribution  of  friable  sandstones,  soft  shales,  etc.,  which 
are  easily  comminuted  but  do  not  persist  as  pebbles  or  boulders. 

Study  of  the  distribution,  structure,  composition,  and  mode 
of  origin  of  the  several  forms  of  deposits  made  by  glaciers  and 
their  attendant  waters,  besides  its  general  application,  affords 
the  means  of  working  out  the  details  of  local  geologic  history 
and  of  explaining  many  features  of  the  topography  which  are 
of  great  interest,  especially  in  educational  work. 

Exposures  of  interglacial  soils  and  vegetal  deposits  are  rarely 
seen,  and  where  found  should  be  carefully  studied,  as  the  included 
organic  remains  may  afford  important  evidence  as  to  the  climate 
and  consequent  probable  extent  of  deglaciation  of  the  region. 
The  location  of  such  a  deposit  relative  to  its  distance  from  the 


INVESTIGATION    OF    METALLIFEROUS    DEPOSITS  109 

margin  of  the  overlying  drift  may  have  like  import,  even  if  the 
deposit  is  not  exposed  but  only  known  to  have  been  penetrated 
in  drillings.  Where  no  organic  remains  occur  the  degree  of 
weathering  and  of  leaching  of  calcareous  drift  in  connection  with 
a  buried  soil  may  afford  data  as  to  the  interval  elapsing  between 
the  melting  of  the  earlier  sheet  and  the  burial  of  the  drift  by 
subsequent  deposition. 

Schedule  4  (p.  126)  indicates  phenomena  on  which  observations 
should  be  made  where  there  is  opportunity. 


INVESTIGATION  OF  PRECIOUS  AND  SEMIPRECIOUS 
METALLIFEROUS  DEPOSITS 

After  as  thorough  a  study  of  the  general  geology  of  the  district 
as  possible  has  been  made,  the  following  points  in  connection 
with  the  ore  deposits  should  receive  special  attention: 

Openings  in  rocks.  Since  most  ore  bodies  are  deposited  by 
aqueous  solutions,  the  channels  through  which  such  solutions 
circulate  are  of  great  importance.  An  opening  of  any  kind  may 
serve  as  the  seat  of  ore  deposition.  A  cave  in  limestone,  a  per- 
meable bed,  such  as  a  sandstone,  a  conglomerate,  or  an  amygda- 
loid, may  furnish  the  open  spaces  necessary,  but  most  of  the 
metalliferous  ore  deposits  are  related  to  openings  which  have 
resulted  from  movement.  It  is  desirable  to  study  the  character 
of  the  openings  and  their  relations  to  each  other,  to  jointing, 
and,  if  they  are  in  sedimentary  rocks,  to  bedding.  It  is  not  always 
possible  to  obtain  data  regarding  the  fissure  itself,  for  processes 
which  attend  deposition  frequently  obscure  the  evidence  of 
fissuring  and  the  ore  body  may  be  the  only  evidence  of  the  open- 
ing which  remains.  This  is  especially  true  of  replacement  veins 
in  limestone. 

In  some  places  certain  rocks  have  been  formed  more  recently 
than  the  ores,  and  where  this  is  so  it  is  desirable  to  establish  the 
fact  as  definitely  as  possible,  for  it  is  obviously  of  great  economic 
importance.  Again,  some  rocks  because  of  their  greater  crushing 
strength  are  better  adapted  to  holding  fissures  open  than  are 
other  rocks.  A  porphyry,  a  limestone,  or  a  quartzite  may  have 


110  INSTRUCTIONS   FOR    SPECIAL    INVESTIGATIONS 

a  high  crushing  strength  and  so  hold  the  fissure  open  and  permit 
mineralization,  whereas  in  shale,  which  is  more  mobile,  the  open- 
ing may  be  closed.  It  is  important,  therefore,  to  note  any  changes 
rin  the  character  of  the  lode  as  it  passes  from  one  rock  to  another. 

Fissures  more  recent  than  the  ore  body  may  cross  it  and  brec- 
ciate  the  ore.  These  should  be  carefully  studied  and  located 
on  the  mine  map.  If  there  has  been  displacement  along  them, 
its  character,  direction,  and  extent  should,  for  obvious  reasons, 
be  studied  with  especial  care.  For  convenience  the  veins  have 
been  divided  into  simple  fissure  fillings  and  replacement  or  meta- 
somatic  veins;  but  it  should  be  borne  in  mind  that  the  two 
classes  are  connected  by  transition  forms. 

Simple  fissure  fillings.  The  wall  rock  of  an  ore  body  has 
nearly  always  been  changed  by  the  solutions  which  deposited 
the  ore,  but  if  the  country  rock  is  not  extensively  replaced  by 
ore  minerals  the  vein  may  be  called  a  fissure  filling,  (a)  The 
thin,  tabular  form  is  more  or  less  characteristic  of  such  a  deposit. 
(6)  The  contact  with  the  country  rock  is  usually  sharp  and 
distinct,  (c)  Angular  fragments  of  the  walls  which  were  broken 
off  and  lodged  in  the  vein  may  be  but  little  altered,  so  that  their 
edges  still  remain  sharp,  (d)  Cavities  with  crusted  banding 
and  well-formed  crystals  pointing  to  the  center  may  ordinarily 
be  taken  as  good  evidence  that  the  ore  was  deposited  in  an  open 
space,  and  crustiform  banding  of  the  vein  parallel  to  the  walls 
usually  indicates  the  same  thing. 

Many  of  the  fissure  veins  in  the  west  were  formed  at  moderate 
depth  and  in  open  spaces  which  presumably  connected  freely 
with  the  surface.  Certain  minerals  are  formed  under  such  con- 
ditions, and  these  are  discussed  briefly  on  page  112. 

Replacement  veins.  Replacement  veins  have  been  formed 
by  solutions  which  circulated  through  openings  in  rocks  but 
which  also  had  the  power  of  dissolving  the  wall  rock  and  replac- 
ing it  with  ore.  All  rocks  are  replaceable  under  some  condi- 
tions, but  a  given  solution  will  not,  as  a  rule,  replace  all  kinds 
of  rock.  Replacement  veins  may  therefore  be  found  in  igneous 
rocks,  in  limestones,  in  quartzites,  or  in  shales,  but  it  is  rarely 
that  all  these  rocks  are  replaced  in  one  mining  district. 

The    openings    through    which    the    solutions    circulated    may 


INVESTIGATION    OF    METALLIFEROUS    DEPOSITS     111 

have  been  very  small,  while  the  resulting  deposit  is  comparatively 
large.  Still,  the  deposits  are  related  to  fissures,  and  in  a  broad 
way  they  resemble  fissure  fillings.  Many  of  them  are  thin  tabu- 
lar in  form,  but  they  are  apt  to  be  much  less  regular  in  detail 
than  fissure  fillings,  (a)  The  nodular  shape  due  to  irregular 
swellings  along  both  dip  and  strike  is  more  or  less  characteristic, 
(6)  The  contact  with  the  wall  rock  is  as  a  rule  gradational  and 
not  sharp  and  distinct,  as  in  fissure  fillings,  (c)  Small,  angular 
fragments  of  the  country  rock  surrounded  by  vein  material 
are  not  often  found  in  such  deposits,  except  where  there  has 
been  brecciation  since  the  ore  was  formed.  Obviously,  such 
small  pieces  of  replaceable  rock  would  have  been  very  readily 
attacked  by  the  replacing  solutions,  (d)  Cavities  are  sometimes 
found  in  such  deposits,  but  they  have  been  formed  by  movement 
or  by  solution  since  the  ore  was  deposited,  or  they  represent 
unfilled  portions  of  the  opening  along  which  the  replacing  solu- 
tions circulated,  (e)  At  favorable  places,  especially  where  dust 
has  collected  on  the  wall,  it  may  be  possible  to  observe  the  bed- 
ding and  jointing  of  the  replaced  rock  in  the  ore  body,  which  is 
in  a  broad  way  pseudomorphous  after  the  soluble  rock. 

Many  replacement  deposits  in  limestone  follow  the  original 
bedding  of  the  rock.  This  may  be  due  to  varying  permeability 
or  solubility  of  beds.  Very  commonly  the  roof  above  such  a 
deposit  is  a  relatively  impervious  shale.  Many  bedding-plane 
deposits,  however,  seem  to  be  related  to  planes  of  movement 
or  bedding-plane  faults.  The  irregular  pockets  or  chimneys  of 
ore  replacing  limestone  may  be  puzzling,  for  the  fissures  or  vein- 
lets  which  lead  to  them  may  be  very  small  indeed  in  comparison 
with  the  chamber  of  ore,  but  when  they  are  worked  out  com- 
pletely some  opening  through  which  the  solutions  may  have 
entered  is  nearly  always  found.  The  minerals  of  replacement 
veins  do  not  always  differ  markedly  from  those  of  fissure  fillings. 
Replacement  veins  as  a  class  are  connected  by  all  gradations,  both 
of  form  and  mineralogy,  with  filled  veins  on  the  one  hand  and  with 
replacement  deposits  of  contact-metamorphic  origin  on  the  other. 

Replacement  deposits  of  contact-metamorphic  origin. 
These  deposits  occur  in  various  rocks  near  intrusive  igneous 
masses,  but  particularly  in  limestones.  As  a  rule  they  are  at 


112     INSTRUCTIONS    FOR    SPECIAL    INVESTIGATIONS 

or  very  close  to  the  contact,  but  some  are  known  several  hundred 
yards  away.  The  ore  minerals  are  so  intergrown  with  silicates 
'  characteristic  of  contact-metamorphic  action  as  to  show  that 
all  were  formed  contemporaneously  under  the  influence  of  the 
'  hot  igneous  mass.  In  shape  the  ore  bodies  are  very  irregular 
in  detail,  and  most  of  them  are  not  clearly  related  to  fissuring. 
The  solutions  which  deposited  them  were  so  hot  and  under  so 
great  pressure  that  presumably  they  could  penetrate  such  minute 
openings  as  the  interstitial  spaces  between  grains  or  the  cleavage 
cracks  of  minerals.  The  deposits,  therefore,  do  not  depend  so 
directly  on  fissuring  of  the  country  rock,  and  they  may  not  be 
even  broadly  tabular.  Some  of  the  minerals  formed  in  such 
deposits  are  discussed  below. 

Mineralogical  study.  The  mineralogy  of  the  ore  should  be 
studied  both  for  scientific  and  practical  purposes.  The  value  of 
the  ore  may  be  ascertained  partly  by  a  knowledge  of  \he  value 
of  the  minerals  contained,  but  frequently  assays  may  be  neces- 
sary if  accurate  information  on  this  point  be  desired.  The 
mineral  composition  will  also  suggest  suitable  metallurgical  pro- 
cesses for  saving  the  values,  and  any  data  at  hand  should  be 
recorded  for  the  use  of  the  metallurgist. 

Investigation  has  shown  that,  although  most  minerals  may 
form  under  various  circumstances,  certain  minerals,  and  par- 
ticularly certain  groups  of  minerals,  are  characteristic  of  certain 
physical  conditions.  They  may  accordingly  be  used  as  indicative 
of  the  conditions  under  which  ores  containing  them  were  deposited. 
Lindgren  *  gives  the  subjoined  list  of  persistent  minerals.  Since 
they  are  formed  under  many  conditions  they  have  little  diag- 
nostic value  in  showing  the  genesis  of  a  deposit.  They  are  pyrite, 
chalcopyrite,  bornite,  arsenopyrite,  galena,  zinc  blende,  gold, 
quartz,  fluorite,  and  muscovite. 

Minerals  more  or  less  characteristic  of  contact-metamorphic 
deposits  and  veins  deposited  under  great  temperature  and  pres- 
sure are,  according  to  Lindgren,  pyrrhotite,  magnetite,  specularite, 
garnet,  andalusite,  staurolite,  tremolite,  diopside,  epidote,  scapo- 
lite,  tourmaline,  etc. 

*  The  relation  of  ore  deposition  to  physical  condition;  Econ.  Geology,  vol.  2, 
1907,  p.  105. 


INVESTIGATION    OF    METALLIFEROUS    DEPOSITS     113 

The  following  minerals,  in  addition  to  the  persistent  minerals, 
may  be  found  in  fissure  fillings  or  in  replacement  veins  formed 
at  relatively  low  pressure:  Marcasite,  cinnabar,  tellurides,  silver 
and  copper  arsenates  and  antimonates,  stibnite,  argentite,  chlorite, 
epidote,  adularia,  celestite,  dolomite,  siderite,  etc.  Among  the 
minerals  which  may  result  from  secondary  enrichment  or  other 
processes  that  are  dependent  on  oxygenated  waters  are  quartz, 
ohalcedony,  limonite,  pyrolusite,  cuprite,  kaolin,  gold,  silver, 
copper,  pyrite,  galena,  chalcopyrite,  bornite,  covellite,  chalcocrte, 
argentite,  with  sulphates,  carbonates,  phosphates,  aresenates, 
and  chlorides  of  the  metals. 

Secondary  enrichment.  As  a  deposit  is  eroded  some  min- 
erals go  into  solution  more  readily  than  others.  Gold,  which 
is  relatively  insoluble,  may  remain,  while  some  of  the  other 
constituents  are  removed.  Thus  a  concentration  takes  place. 
As  the  sulphides  oxidize  sulphate  solutions  are  formed,  and  these 
may  dissolve  small  quantities  of  the  precious  metals.  If  the 
lode  is  much  fractured  the  descending  sulphates  may  be  reduced, 
the  solutions  depositing  part  of  their  burden  in  the  cracks  of  the 
lode.  Thus  these  fractures  in  the  lode  will  contain  a  set  of  min- 
erals, some  of  which  are  different  from  those  of  the  primary  ore. 
These  minerals  are  included  in  the  list  of  secondary  minerals 
given  above.  It  may  happen  that  the  deposit  is  explored  in  depth 
beyond  the  point  where  it  is  extensively  fractured  or  beyond 
the  point  to  which  oxygenated  waters  descend;  in  this  case 
the  primary  minerals  alone  will  be  found.  It  is  obviously  impor- 
tant to  note  the  differences  in  value  of  the  primary  and  secondary 
ore,  so  that  some  general  recommendations  as  to  the  desirability 
of  exploration  in  depth  may  be  made. 

Pay  Shoots.  Few  veins  are  payable  through  the  entire  length 
of  the  strike  or  dip,  the  profitable  ore  being  ordinarily  limited 
to  a  certain  portion  of  the  vein.  Such  masses  of  valuable  ore 
are  called  pay  shoots  and  in  many  veins  form  tabular  bodies  of 
fairly  regular  elongated  outline.  The  inclination  of  a  pay  shoot 
from  the  horizontal  on  the  plane  of  the  vein  is  called  the  pitch. 
Its  longest  dimension  is  called  the  pitch  length;  the  term  "stope 
length"  refers  to  its  horizontal  dimension  along  the  drift  follow- 
ing it.  Pay  shoots  may  result  from  primary  deposition  or  from 


114     INSTRUCTIONS    FOR    SPECIAL    INVESTIGATIONS 

secondary  enrichment  by  surface  waters.  The  origin  of  pay 
shoots  is  not  always  easy  to  ascertain.  Many  of  them  may  be 
attributed  to  mingling  of  the  solutions  which  deposited  the 
.  primary  ore.  The  enriched  portion  of  the  deposit  is  often  found 
along  or  in  close  proximity  to  intersections  of  two  fissures  that 
were  paths  for  circulation.  An  intersection  of  a  fissure  and  a 
bed  which  for  chemical  and  physical  reasons  is  favorable  to 
deposition  may  also  be  a  locus  of  enrichment. 

Commercial  and  metallurgical  considerations.  Wood, 
water,  power,  and  facilities  for  transportation  are  important 
considerations  in  mining  development.  The  success  or  failure 
of  a  camp  sometimes  depends  on  the  success  or  failure  of  a  metal- 
lurgical process.  Gold  ores  of  very  low  grade  may  be  worked 
by  cyanide  processes,  for  the  cost  of  treatment  is  often  not  more 
than  $2  or  $3  per  ton.  Silver  ores  are  more  expensive  to  treat, 
even  if  the  values  are  in  native  silver,  horn  silver,  and  silver 
sulphide — minerals  which  may  yield  their  values  on  amalgamation 
in  pans  without  roasting.  On  the  other  hand,  if  arsenates,  anti- 
monates,  and  other  undesirable  elements  are  present  the  ore 
must  be  roasted  before  amalgamation,  and  the  milling  costs  are 
then  likely  to  be  considerably  higher  than  $6  per  ton.  Zinc 
blende  in  silver  ores  is  detrimental  where  silver  ores  are  shipped 
to  smelters.  Highly  siliceous  ores  are  expensive  to  smelt  because 
they  require  more  flux,  but  very  highly  siliceous  ores  may  be 
used  for  lining  copper  converters  and  for  that  reason  may  have 
additional  value.  Ores  rich  in  iron  and  lime  have  a  low  treat- 
ment charge,  for  these  elements  are  good  fluxes.  Although  the 
geologist  is  not  supposed  to  be  a  metallurgical  expert,  he  should 
record  such  information  regarding  the  treatment  of  the  ores  as 
he  can  gather  in  the  course  of  his  proper  work. 

INVESTIGATION  OF  PLACER  DEPOSITS 

The  study  of  the  general  geology  in  connection  with  placer 
deposits  differs  in  no  way  from  that  of  other  field  work,  except 
that  special  emphasis  should  be  laid  on  the  investigation  of  (a) 
the  distribution  of  the  mineralization  in  the  bed  rock  from  which 
placer  deposits  have  been  derived,  and  (6)  the  distribution  and 


INVESTIGATION    OF    PLACER   DEPOSITS          115 

genesis  of  the  alluvium.  In  connection  with  the  latter  subject 
the  geologist  is  reminded  that  a  careful  search  for  fossils  should 
be  made  and  also  that  physiographic  studies  may  yield  valuable 
results. 

Every  effort  should  be  made  to  obtain  a  complete  and  detailed 
section  of  the  deposit  in  which  the  valuable  mineral  occurs,  from 
the  surface  to  bed  rock.  If  possible,  such  a  section  should  be 
obtained  by  personal  observation  and  actual  measurement.  If 
this  is  not  possible,  the  observations  should  be  supplemented  by 
data  obtained  from  mine  operators,  such  as  records  of  shafts, 
drill  holes,  etc.  The  section  should  show  the  details  of  (a)  the 
cover,  or  overburden;  (b)  the  pay  streak,  or  that  portion  of  a 
deposit  carrying  the  mineral  sought  after;  and  (c)  the  floor  upon 
which  the  pay  streak  rests,  including  a  statement  of  its  surface 
configuration,  texture,  lithology,  etc.  In  addition  to  these  ver- 
tical sections,  attempts  should  also  be  made  to  learn  the  horizontal 
distribution  of  the  deposits,  together  with  their  relations  to  the 
topography.  In  all  this  work  drawings  should  be  made  showing 
detailed  vertical  and  horizontal  relations  of  important  features. 

One  of  the  most  important  economic  results  to  be  achieved  is 
an  estimate  of  the  extent  and  value  of  the  placer  deposits.  Such 
information  is  none  the  less  valuable  because  as  a  rule  it  is  not 
published,  for  the  geologist  can  intelligently  discuss  the  probable 
life  of  any  particular  placer-mining  district  only  by  having  data 
at  hand  which  will  yield  some  information  in  regard  to  both  the 
cubic  content  of  the  deposit  and  the  contained  values.  Effort 
should  therefore  be  made  to  ascertain  the  facts  bearing  on  this 
subject,  and  much  of  the  information  must  necessarily  be  obtained 
from  the  mine  operators. 

Data  bearing  on  the  water  supply  available  for  mining  purposes 
should  be  collected,  and  in  this  connection  climatic  conditions, 
such  as  rainfall  and  temperature,  should  be  considered.  As  in 
other  mining  operations,  the  question  of  fuel  and  timber  supply 
is  important  and  should  receive  consideration.  Facts  which 
will  permit  the  preparation  of  an  accurate  account  of  the  history 
of  the  discovery  and  development  of  the  mining  district  should 
also  be  procured  while  in  the  field.  With  this  work  should  go 
the  collection  of  information  on  production,  especially  in  the 


116     INSTRUCTIONS    FOR    SPECIAL    INVESTIGATIONS 

older  districts,  where  reliable  statistics  of  output  are  usually  not 
available  from  published  reports.  Cost  and  methods  of  mining 
cannot  be  intelligently  discussed  if  the  data  in  regard  to  price 
,  of  labor,  transportation,  and  supplies  are  not  at  hand,  and  these 
subjects  should  therefore  receive  attention.  This  investigation 
will  necessitate  a  consideration  of  the  geographic  position  relative 
to  navigable  waters,  railways,  wagon  roads,  trails,  etc. 

INVESTIGATION  OF  OIL  AND  GAS  FIELDS 

A  comprehensive  knowledge  of  the  general  geology — especially 
of  the  stratigraphy  and  structure — is  highly  essential  as  a  basis 
for  work  on  oil  and  gas  fields.  The  stratigraphy  must  be  known 
in  order  to  interpret  well  logs  correctly  and  to  determine  (a)  the 
character  of  the  oil  or  gas  bearing  stratum  and  its  capacity  for 
holding  and  yielding  the  hydrocarbons,  and  (&)  the  character 
of  the  overlying  beds  and  their  adaptability  for  retaining  these 
compounds.  The  beds  concerned  as  reservoirs  and  cover  should 
be  carefully  studied  and  their  thickness  determined  on  the  out- 
crop. This  may  be  at  a  considerable  distance  from  the  oil  or 
gas  pool,  and  the  beds  should  be  traced  from  the  outcrop  to  the 
pool  under  investigation  by  the  collection  of  as  many  logs  of 
wells  in  the  intervening  region  as  possible.  In  general  the  col- 
lection of  logs  of  wild-cat  wells  outside  of  the  productive  terri- 
tory is  especially  desirable.  The  importance  of  structure  is  such 
that  it  must  be  determined  with  a  much  greater  degree  of  accuracy 
than  is  generally  necessary  for  other  purposes.  In  most  oil  and 
gas  fields  the  structures  are  not  sufficiently  pronounced  to  be 
traced  by  determining  dips  with  a  clinometer.  It  is  therefore 
necessary  to  connect  the  outcrops  of  some  easily  identifiable  bed 
by  level  lines,  which  are  also  tied  to  all  wells  whose  logs  can  be 
obtained.  The  method  of  obtaining,  from  surface  observations 
and  well  logs,  a  contoured  representation  of  the  oil  or  gas  sand 
is  fully  explained  by  W.  T.  Griswold  in  U.  S.  Geological  Survey 
Bulletin  No.  318,  and  should  be  familiar  to  the  geologist  working 
in  fields  to  which  it  is  applicable. 

In  certain  oil  fields — for  example,  in  southern  California,  where 
the  oil  occurs  in  post-Paleozoic  rocks — the  structures,  both  folds 


SCHEDULES  117 

and  faults,  may  be  so  strongly  developed  that  they  are  readily 
determined  by  ordinary  means  and  without  leveling.  In  others, 
as  in  southeastern  Texas,  no  means  are  available  for  determining 
structure  except  the  well  logs  and  surface  relief.  The  relief  should 
therefore  be  minutely  examined,  together  with  all  indications 
furnished  by  mineral  springs,  oil  seeps,  etc. 

Tact  is  required  in  obtaining  information  from  operators  and 
drillers.  They  should  be  impressed  with  the  benefit  to  them- 
selves that  will  result  from  the  assembling  of  all  available  infor- 
mation regarding  the  underground  conditions  of  the  field  and 
with  the  necessity  for  their  cooperation.  They  should  be  assured 
that  confidential  information  will  not  be  divulged  under  any 
circumstances  and  must  never  be  given  ground  for  complaint 
on  this  score.  Explicit  permission  should  be  obtained  from  the 
owner  or  superintendent  before  questioning  drillers,  but  when 
it  is  obtained  they  should  be  questioned  thoroughly. 

SCHEDULES 

The  following  schedules  cover  the  more  important  subjects 
and  classes  of  deposits  which  will  come  under  the  observation 
of  field  geologists.  Observations  on  other  deposits  should  follow 
the  general  lines  indicated  in  these  schedules. 

A.  Pure  geology: 

1.  Description  and  interpretation  of  land  forms. 

2.  Petrology. 

3.  Structure. 

4.  Glaciers  and  glacial  deposits. 

B.  Applied  geology: 

5.  Precious  and  semiprecious  metalliferous  ores. 

6.  Placer  deposits. 

7.  Iron  ores,  ocher,  manganese  ore,  and  bauxite. 

8.  Stone:  (a)  Sedimentary  rocks ;    (6)   igneous  rocks. 

9.  Road  materials:    (a)  Rock;   (6)  gravel. 

10.  Cement  materials  and  lime. 

11.  Clay  and  shale. 

12.  Sand  and  gravel. 

13.  Coal. 

14.  Oil  and  gas. 


SCHEDULE  1.     Description   and   interpretation   of   land 

forms. 

1.  Location:  District,  quadrangle,  map  reference. 

2.  Relief. 

I.  General. 

(1)  Amount  with  reference  to  sea  level  and  local  grade 

level. 

(2)  Character — plain,   plateau,   mountain;    proportion 

of  each  kind. 

(3)  Areal  relations  (often  best  illustrated  by  sketch). 
II.  Component  parts. 

(1)  Upland:  (a)  Area  of  undissected  surface  and  ground 

plan;  (6)  slope — direction  and  amount;  (c)  re- 
lation to  structure  and  lithology — faults,  folds, 
texture,  etc.;  (d)  residual  destructional  forms 
— monadnocks,  old  stream  channels,  benches, 
scarps,  etc.;  (e)  residual  constructional  forms 
— terraces,  deltas,  dunes,  beaches,  fans,  lava 
flows,  volcanoes,  etc.;  (/)  soils  and  vegetation; 
(g)  origin — glacial,  marine,  eoliari,  fluviatile, 
lacrustine,  volcanic,  etc. 

(2)  Valleys:    (a)  General   areal   distribution;    (b)  size 

of  main  and  side  valleys  and  ground  plan; 
(c)  slope  of  walls  and  floor;  (d)  relation  to 
structure  and  lithology;  (e)  constructional  and 
destructional  forms;  (/)  relation  of  size  of  val- 
leys to  size  of  streams;  (g)  captures  and  incip- 
ient captures;  (h)  stage  of  development — 
—young,  mature,  old,  etc.;  (i)  soils  and  vege- 
tation; (j)  origin. 

(3)  Spurs:     (a)    Size;     (b)    shape — skeletal,    massive, 

faceted,  straggling,  etc.;  (c)  slope — smooth, 
steep,  benched,  irregular,  etc.;  (d)  relation  to 
structure  and  lithology;  (e)  origin. 

III.  Relation  to  adjacent  regions  or  types:  (a)  Gradual  merg- 
ing, boundary  ill  defined;  (b)  terminated  by 
the  sea,  folding,  faulting. 

118 


SCHEDULES  119 

3.  Relation  of  environment  to  life. 

I.  Man:  (a)  Occupations — mining,  grazing,  agriculture, 
hunting,  etc.;  (6)  constructions — roads,  rail- 
roads, ditches,  buildings,  wells,  power  plants, 
etc.;  (c)  peculiar  characters. 

II.  Animals  and  plants  (very  brief  treatment  of  larger  charac- 
ters only):  Kinds,  distribution,  peculiar  char- 
acters. 

4.  Historical  summary. 

I.  Physiographic  cycles:  (a)  Number  and  extent ;  (6)  stage 
reached  in  each — youth,  maturity,  etc.;  (c) 
forms  belonging  to  each;  (d)  origin. 

II.  Interruption  of  cycle  caused  by  (a)  uplift — doming,  fold- 
ing, faulting,  etc. ;  (6)  depression — folding,  fault- 
ing, differential  tilting,  etc.;  (c)  volcanism — 
extrusion,  eruption,  effusion,  etc.;  (d)  climatic 
change — glaciation  deglaciation,  desiccation,  in- 
creased precipitation  or  run-off. 


SCHEDULE  2.     Petrology 

1.  Location:    (a)  Quadrangle  or  other  map  reference ;    (6)  with  ref- 

erence to  topography;  (c)  nature  of  exposures  or  section, 
method  of  measurements — horizontal,  vertical,  angular. 

2.  Igneous  rocks. 

(1)  Petrographic  character :    (a)  Mineral  composition ;  (6)  tex- 

ture; (c)  variations  in  composition  and  texture;  (d) 
specimen  numbers. 

(2)  Mode  of  occurrence :   (a)  Form — batholith,  laccolith,  sheet, 

dike,  neck,  etc.;  (fr)  size;  (c)  position. 

(3)  Relations:  (a)  To  other  igneous  rocks;  (b)  to  other  forms 

of  the  same  rock ;  (c)  to  associated  sediments ;  (d)  inclu- 
sions. 

(4)  Contact  metamorphism :  (a)  In  the  igneous  rock;  (6)  in 

the  associated  rocks — alteration  of  form,  addition  of 
mineral  substance,  substitution  of  mineral  substance 
(injection). 

(5)  Decomposition:     (a)  Hydrothermal ;    (6)  decay;    (c)  me- 

chanical disintegration;    (d)  character  of  resulting  soil. 

(6)  Origin  (inferred):    (a)  Plutonic;    (&)  effusive. 

3.  Sedimentary  rocks. 

I.  Clastic  rocks;    make  numerous  detailed  measured  sections, 
observing  and  noting — 

(1)  Petrographic  character:    (a)  Essential  constituent  min- 

eral grains — size,  shape,  color,  arrangement,  etc.; 
(6)  accessory  constituents;  (n)  cement — primary  or 
secondary;  (d)  veins — composition,  amount,  color, 
etc.;  (e)  color — original  or  secondary;  (/)  specimen 
numbers. 

(2)  Badding:   (a)   Beds — thickness,  uniformity,  regularity, 

relation  to  size  of  grains,  etc.;  (&)  bedding  planes — 
mud  covered,  micaceous,  ripple  or  current  marks, 
mud  cracks,  rain  pits,  trails,  borings,  tracks,  fucoids, 
etc.;  (c)  cross-bedding — dip,  direction,  etc. 

(3)  Fossils;    make  abundant   collections  and  observe   (a) 

distribution;  (6)  position;  (c)  if  waterworn;  (d)  in 
pebbles,  etc. 

120 


SCHEDULES  121 

3.  Sedimentary  rocks — Continued. 
I.  Clastic  rocks — Continued. 

(4)  Concretions:     (a)    Composition — siliceous,    calcareous, 

phosphatic,  pyritic,  etc.;  (b)  form,  distribution, 
abundance;  (c)  relation  to  particular  beds,  to  fossils, 
etc. 

(5)  Unconformities:    (a)  By  erosion  of  under  beds;    (6)  by 

overlap  of  upper  beds;  (c)  angle;  (d)  extent — gen- 
eral or  local;  (e)  relation  to  conglomerates. 

(6)  Special  structures:    (a)  Contorted  beds;    (6)  indigenous 

conglomerates;  (c)  lenses,  etc. 

(7)  Origin  (inferred):    (a)  Source  of  materials;    (b)  agency 

of  transportation  and  deposition— marine  beach, 
streams,  wind,  glaciers,  etc. ;  (c)  conditions  at  source 
of  material  and  point  of  deposition. 

(8)  Classification  and  correlation:     (a)   Formation,  name; 

(6)  limits ;  (c)  compare  and  contrast  with  correspond- 
ing sections  elsewhere. 
II.  Chemical  and  organic  rocks. 

(1)  Petrographic    character:     (a)    Essential    mineralogical 

constituents;  (b)  accessory  constituents;  (c)  tex- 
ture; (d)  variations  in  composition  and  texture;  (e) 
color — original  or  secondary;  (/)  specimen  numbers. 

(2)  Bedding:    (a)  Beds — thickness,  uniformity,  regularity; 

(b)  bedding  planes. 

(3)  Fossils;    make  abundant  collections  and  observe   (a) 

distribution ;    (b)  relation  to  composition  of  beds,  etc. 

(4)  Concretions:    (a)  Composition;    (b)  form;    (c)  relations, 

etc. 

(5)  Unconformities:  (a)  Erosion;  (b)  overlap;  (c)  extent,  etc. 

(6)  Special  structures. 

(7)  Origin   (inferred):    (a)   Source  of  materials — essential, 

secondary;  (b)  conditions  of  deposition — conti- 
nental, estuary,  inclosed  basin,  playa,  flood  plain, 
swamp,  etc.;  marine,  deep  sea,  littoral,  reef,  etc. 

(8)  Classification  and  correlation;    (a)   Formation,  name; 

(6)  limits;  (c)  compare  and  contrast  with  corre- 
sponding sections  elsewhere. 


SCHEDULE  3.     Structure 

1.  Location:  Map  reference. 

2.  Monoclines. 

(1)  Facts  to  be  observed:  (a)  Of  the  beds — dip,  strike,  waving, 

etc. ;  (6)  of  the  structure  as  a  whole — length,  regularity, 
terminations,  relation  to  faults,  folds,  relation  to  topog- 
raphy, etc. 

(2)  Classification  based  on  observation  and  inference — simple, 

warped,  faulted  (basin-range  structure). 

3.  Folds. 

(1)  Facts  to  be  observed:   (a)  Of  beds — dip,  strike,  crumpling, 

thinning;  (b)  of  axes — position,  direction,  pitch;  (c)  of 
the  folds  as  a  whole — length,  regularity,  overlapping, 
relation  to  topography,  etc. 

(2)  Classification  based  on  observation  and  inference — order  of 

magnitude  (major  or  minor),  symmetrical  or  unsym- 
metrical  (axial  plane,  vertical  or  inclined),  overturned, 
closed  (isoclinal),  domed  (quaquaversal),  cross,  pitching, 
Echelon,  faulted,  etc. 

4.  Faults. 

(1)  Facts  to  be  observed:    (a)  By  direct  observation  where 

exposures  permit — dip  or  hade  (complement  of  dip), 
strike,  throw,  brecciation,  drag,  slickensides,  relation  to 
bedding,  relation  to  other  structures  (folds  and  faults), 
joints;  (fr)  by  indirect  determination  where  exposures 
are  poor — dip,  strike,  throw,  direction  of  displacement, 
length,  regularity,  relation  to  other  structures  and  to 
topography  (scarps,  stream  courses,  etc.). 

(2)  Classification  based  on  observation  and  inference — order 

of  magnitude  (major  or  minor),  normal  (dip  toward 
down-throw),  reverse  (dip  from  down-throw),  lateral 
(movement  tangential),  overthrust,  warped,  etc. 

122 


SCHEDULES  123 

,c.  Joints  and  fissures. 

(1)  Facts  to  be  observed:  (a)  Dip,  strike,  spacing,  extent,  uni- 
formity (curved  or  straight),  etc.;  (6)  relation  to  bed- 
ding arid  lit  ho  logic  character;  (c)  mineralization;  (c?) 
different  systems,  character  of  intersections,  relative  age ; 
(e)  relation  to  other  structures,  folds  and  faults,  etc.; 
(/)  effect  on  erosion,  character  of  topography,  stream 
courses,  etc. 

6.  Metamorphism  (dynamic). 

(1)  Facts  to  be  observed  regarding  structures  resulting  from 
metamorphism :  (a)  Attitude — dip,  strike,  regularity, 
etc.;  (b)  relation  to  bedding,  local  folds,  general  struc- 
tures ;  (c)  mineral  changes — component  minerals,  origi- 
nal minerals  (inferred),  nature  of  change  (addition, 
subtraction,  or  recombination),  parallelism  and  rota- 
tion of  minerals,  augen,  striation,  granulation,  banding, 
pitch  (pencil  structure),  etc. 


SCHEDULE  4.     Glaciers  and  glacial  deposits 

1.  Location:  Map  reference  or  description. 

2.  Kind:  (a)  Mountain;  (b)  continental. 

A.  Mountain  glaciers. 

I.  Existing  glaciers:  (a)  Condition — advancing,  station- 
ary, retreating;  (b)  surface,  crevasses — character 
and  extent ;  (c)  margins — lateral,  terminal,  relation 
to  neve,  bergschrund;  (d)  activity  in  eroding, 
transporting,  depositing;  (e)  relations  to  surround- 
ing topography,  other  glaciers,  etc. 
II.  Former  glaciers: 

(1)  Extent:    Inferred  from  (a)  erosion  forms;    (b) 

deposits. 

(2)  Readvances:   Overridden  (a)  outwash  deposits, 

(6)  lacustrine  deposits;    (c)  marsh  or  forest. 
III.  Deposits: 

(1)  Moraines:    (a)  Class — terminal,  medial,  lateral, 

ground;  (6)  distribution,  size,  structure,  com- 
position ;  (c)  relative  strength  and  spacing  of 
inner  moraines;  (d)  presence  of  material  for- 
eign to  basin. 

(2)  Extramorainal  deposits  (outwash) :    (a)  Charac- 

ter, coarseness ;  (b)  relation  to  present  stream 
terraces,  etc. 

(3)  Glaciolacustrine  deposits:    (a)  Beaches,  deltas, 

etc.;  (b)  distribution,  structure,  composition, 
etc. ;  (c)  relation  to  other  glacial  deposits. 

(4)  Evidence  of  relative  age:    (a)  Weathering;    (b) 

erosion. 
IV.  Erosion:    (a)  Striae;    (6)  rock  basins;  (c)  roches  mou- 

tonne"es;  (d)  cirques;  (e)  U-shaped  valleys. 
V.  Hanging  valleys. 

B.  Pleistocene  continental  glaciation. 

I.  Direction  of  movement:  (a)  Striations;  (6)  etoss  and 
lee  slopes;  (c)  trend  of  drumlins,  eskers,  etc.;  (d) 
transportation  of  erratics. 

124 


SCHEDULES  125 

2.  Kind:  (a)  Mountain;  (6)  continental — Continued. 
B.  Pleistocene  continental  glaciation — Continued. 

II.  Erosion  features:  (a)  Glaciated  surfaces — planing,  pol- 
ishing, striation,  fluting,  chatter  marks,  gouging, 
rock  basins,  roches  moutonnees,  etc.;  (6)  plucking 
— relation  to  joints,  bedding,  schistosity,  etc.;  (c) 
effects  of  structure  and  lithologic  character;  (cZ) 
amount — variation . 

III.  Ice  push:   Folding,  crumpling,  or  other  dislocation  of 

consolidated  or  unconsolidated  beds. 

IV.  Deposits:  Composition  and  structure  of  each  class: 

(1)  Moraines:    (a)  Terminal — surface  form,  relation 

to  underlying  glacial  deposits,  relation  to  pre- 
glacial  topography,  reentrants  and  lobations; 
(fr)  recessional — relative  strength,  spacing,  re- 
lation to  other  glacial  deposits;  (c)  interlo- 
bate. 

(2)  Drumlins,  eskers,  kames:   (a)  Form,  size,  orien- 

tation; (6)  distribution  relative  to  glaciated 
area;  (c)  to  terminal  moraines;  (d)  to  other 
drift  features;  (e)  to  preglacial  topography, 
etc. 

(3)  Extramarginal  deposits :   (a)  Glacio fluvial — out- 

wash  deposits ;  (fr)  glaciolacustrine — beaches, 
bars,  deltas,  etc. 

(4)  Associated  loess:   Relations  to  glacial  drift,  to- 

pography, and  drainage  lines. 
V.  Age  of  drift: 

(1)  Not  overlain  by  later  drift:    (a)  Oxidation:    (fc) 

leaching ;  (c)  solution  of  limestone  fragments ; 
(d)  decay  of  crystalline  rock  fragments;  (e) 
induration. 

(2)  Overlapping  drift  sheets:    (a)  Weathering  and 

erosion  of  earlier  prior  to  deposition  of  later; 
(6)  intercalated  soil,  peat,  forest,  marine  or 
lacustrine  beds ;  (c)  difference  in  composition 
due  to  different  origin ;  (d)  relation  to  loess. 


SCHEDULE  5.     Precious  and  semiprecious  metalliferous 

ores 

1.  Location:   (a)  District,  State,  county,  etc.;   (b)  name  of  claim  or 

mine;    (c)  map  reference;    (d)  names  of  owner,  operator,  and 
superintendent. 

2.  Geologic  relations. 

(1)  Rock  formations  (see  Schedule  2) :    (a)  Igneous,  sedimen- 

tary, metamorphic;   (6)  contact  relations;  (c)  age. 

(2)  Structure  (see  Schedule  3). 

(3)  Metamorphism :  Regional,  contact,  hydrothermal. 

(4)  Weathering. 

3.  Ore  deposits. 

(1)  Outcrop:    Leached,  enriched,  oxidized,  yielding  placers, 

etc.    • 

(2)  Form:   Tabular,  elongated,  cylindrical  lenticular,  pockets, 

stockworks,  irregular  masses,  etc. 

(3)  Attitude:  Dip,  strike,  pitch,  etc. 

(4)  Position  with  respect  to  fissuring,  faulting,  sheeting,  bed- 

ding, etc. 

(5)  Distribution  with  respect  to  (a)  age  and  kind  of  rocks ;  (6) 

system  and  age  of  fissures;    (c)  zones  of  contact  meta- 
morphism,  etc. 

(6)  Minerals :  (a)  In  vein  and  wall  rock ;  (b)  vertical  variations ; 

(c)  relations  to  each  other  and  to  fracturing  of  vein ;   (d) 
lower  limit  of  oxidation ;   (e)  level  of  ground  water. 

(7)  Genesis,  based  on  observation  and  inference. 

(A)  Superficial:    (a)  Placers  and  residual  deposits  (see 

Schedule  6);  (b)  deposits  formed  by  precipita- 
tion and  allied  processes. 

(B)  Inclosed :  (a)  Contemporaneous  with  inclosing  rocks 

— sedimentary  or  magmatic;  (6)  introduced  by 
solutions — contact-metamorphic  replacement  de- 
posits, replacement  veins  and  related  deposits, 
fissures  and  other  cavity  fillings,  impregnations 
and  disseminations  along  favorable  beds,  etc. ;  (c) 
pegmatite  veins. 

126 


SCHEDULES  127 

3.  Ore  deposits — Continued. 

(8)  Pay  shoots:  (a)  Primary  or  secondary;  (6)  variation  in 
mineralogical  character  with  depth,  upper  and  lower 
limits ;  (c)  position  with  respect  to  the  deposit  as  a  whole, 
to  fissures  (especially  to  their  intersections),  and  to 
changes  in  wall  rocks. 

4.  Conditions  affecting  mining:  (a)  Topography,  accessibility,  trans- 

portation facilities,  building  sites,  dumps,  etc.;  (6)  supplies — 
timber,  water,  fuel,  power,  etc.;  (c)  climatic  conditions — work- 
ing season,  frozen  ground,  etc. 

5.  Development. 

(1)  Surface  equipment:    (a)  Hoist — bucket,  cage,  skip;    (6) 

tramways — surface  or  aerial,  length,  power. 

(2)  Mine  equipment:    (a)  Shaft — size,  depth,  number  of  com- 

partments, equipment,  pumps,  etc.;  (6)  incline— slope, 
direction,  length,  depth,  equipment,  etc.;  (c)  tunnel — 
length,  size,  etc. ;  (d)  winzes,  upraises,  and  chutes — num- 
ber, position,  length,  uses;  (e)  levels — number,  differ- 
ences in  elevation,  depth  below  surface,  etc. 

6.  Methods :   (a)  Mining — underhand  stoping,  overhead  stoping,  fill- 

ing, rooming,  caving  and  slicing,  etc. ;  (6)  timbering;  (c)  drain- 
ing J  W  ventilating. 

7.  Disposition  of  ore:  (a)  Shipped  to  smelter — by  wagon,  rail,  water; 

(b)  treated  in  mill — by  stamping  and  amalgamation,  cyanidirig, 
chloridizing,  pan  amalgamation,  roasting  and  pan  amalgama- 
tion, leaching  processes,  concentration,  etc. 

8.  History  of  discovery  and  development. 

9.  Production;  Total  and  annual  so  far  as  available. 


SCHEDULE  6.     Placer  deposits 

1.  Location:    (a)  District,  State,  county,  etc.;    (6)  name  of  claim; 

(c)  map  reference;  (d)  name  and  address  of  owner  or  operator. 

2.  Geologic  relations. 

(1)  Rock  formations  (see  Schedule  2). 

(2)  Structure  (see  Schedule  3). 

(3)  Metamorphism :   (a)  Nature — regional,  contact,  hydrother- 

mal;  (6)  mineralized  zones,  veins,  or  other  deposits  cf 
metalliferous  ores. 

(4)  Weathering:  (a)  Rock  decay;  (fr)  rock  disintegration. 

3.  Surficial  deposits. 

(1)  Overburden  or  cover:    (a)  Distribution  and  depth;    (b) 

stratigraphic  relations;  (c)  character — size,  shape,  and 
composition  of  constituent  materials ;  loose  or  cemented 
(nature  of  cement) ;  (d}  genesis — transported  (agency  of 
transportation  and  deposition)  or  residual. 

(2)  Pay  streak  or  part  of  deposit  carrying  values :  (a)  Number ; 

(6)  position — vertical,  horizontal;  (c)  stratigraphic  rela- 
tions; (d)  dimensions,  shape,  etc.;  (e)  character — size, 
shape,  and  composition  of  essential  constituent  mate- 
rials ;  loose  or  cemented  (nature  of  cement) ;  ( /)  valuable 
minerals — percentage  of  each,  physical  character,  size, 
luster,  etc.;  (g)  distribution  of  values  within  the  pay 
streak;  (h)  content  or  value  per  cubic  yard  of  pay  streak. 

(3)  Floor  or  bed  rock:  (a)  Configuration,  slope,  channels,  pot- 

holes or  other  irregularities ;  (6)  origin  of  surface— eroded 
or  consaded  (agency),  glaciated,  weathered  (under  resid- 
ual deposits),  etc. ;  (c)  structure  of  bed  rock  (particularly 
jointing,  cleavage,  etc.) ;  (d)  mineralogical  composition, 
mineralization,  weathering,  etc.;  (e)  depths  to  which 
values  are  found  in  floor  or  bed  rock. 

(4)  Ground  water  (or  ground  ice) :   (a)  Depth  and  distribution ; 

(6)  amount  and  variation. 

4.  Conditions  affecting  mining. 

(1)  Topography,  accessibility,  transportation  facilities,  labor 
and  wages,  etc. 

128 


SCHEDULES  129 

4.  Conditions  affecting  mining — Continued. 

(2)  Water  supply:   (a)  Volume;   (6)  stream  gradient ;   (c)  rela- 

tion to  placer  deposits ;  (d)  kind  of  conduits,  dams,  reser- 
voirs, etc.,  necessary  and  cost  of  construction. 

(3)  Supplies  of  fuel,  lumber,  power,  etc. 

(4)  Climatic  conditions:    (a)  Rainfall — amount  and  distribu- 

tion;   (6)  working  season;    (c)  frozen  ground  or  other 
exceptional  conditions. 

5.  Methods  and  costs  of  prospecting  and  mining. 

I.  Prospecting:    (a)  Methods — pits,  shafts,  drill  holes,  drifts, 
open  cuts,  etc.;    (b)  cost  per  unit  (cubic  yard,  acre,  linear 
foot  of  shaft  or  drilling,  etc.) ;    (c)  reliability  of  results. 
II.  Mining. 

(1)  Preparation  of  ground:   (a)  Methods — clearing,  strip- 

ping, ground  sluicing,  weathering,  thawing,  sink- 
ing, drifting,  etc.;  (b)  cost  per  unit. 

(2)  Excavating  and  handling. 

A.  Open  cut:    (a)  Manual — hand  work  with  pick, 

shovel,  and  barrow;  (b)  hydraulic — ground 
sluicing,  hydraulic  elevators,  etc.;  (c)  me- 
chanical— horse  scrapers,  power  shovels,  lifts, 
conveyors,  trams,  hoists,  derricks  (for  hand- 
ling boulders),  etc.;  (d)  cleaning  bed  rock. 

B.  Drift:     (a)    Sinking    and    drifting — timbering, 

draining,  thawing,  etc.;  (b)  hoisting — hand, 
horse,  or  power;  (c)  cleaning  bed  rock. 

C.  Dredge:   (a)  Type;   (b)  power;   (c)  capacity. 

D.  Cost  per  unit. 

6.  Separation  of  valuable  minerals. 

(1)  Rocking  and  panning. 

(2)  Sluicing:  (a)  Dimensions,  etc.,  of  sluice  boxes,  grade,  riffles, 

dump  boxes,  grizzlies,  under  currents,  etc.;  (6)  distribu- 
tion of  values  in  sluice  boxes;   (c)  disposal  of  tailings. 

7.  Development:    (a)  Extent  of  workings,  open  cuts,  shafts,  drifts, 

area  dredged,  etc.;  (b)  character  and  value  of  equipment, 
including  machinery,  ditches,  roads,  building,  etc.;  annual 
depreciation  of  plant. 

8.  History  of  discovery  and  development. 

9.  Production:  Total  and  annual  so  far  as  available. 


SCHEDULE    7.     Iron  ores,  ocher,  manganese  ore,  and 
bauxite 

1.  Location:    (a)  Map  reference;   (b)  name  of  mine  or  pit,  claim  or 

property;    (c)  names  and  addresses  of  owner  or  operator  and 
superintendent. 

2.  Geologic  relations. 

(1)  Rock  formations  (see  Schedule  2). 

(2)  Structure  (see  Schedule  3). 

(3)  Metamorphism :  Regional,  contact,  hydrothermal. 

(4)  Weathering:    (a)  Decay — character,  depth,  products;    (b) 

disintegration. 

3.  The  deposits;  make  sketches  and  photographs. 

(1)  Outcrop:  (a)  Character,  extent,  etc. ;  (6)  relation  to  topog* 

raphy. 

(2)  Form:    Shape  and  dimensions — veins,  pockets,  irregulart 

bowl  shape,  dendritic,  lenses,  beds,  etc. 

(3)  Attitude:  Dip,  strike,  pitch,  etc. 

(4)  Position  with  respect  to  (a)  structures — faulting,  sheeting, 

brecciation,  jointing,  etc.;  (fe)  particular  beds ;  (c)  other 
deposits  of  the  same  or  other  minerals. 

(5)  Overburden:  Depth,  character,  etc. 

4.  The  ore;  collect  samples  for  chemical  and  microscopic  examina- 

tion. 

(1)  Composition:    (a)  Essential  ore  minerals;    (6)  accessory 

minerals;  (c)  ore  siliceous,  calcareous,  aluminous;  (d) 
waste  material — clay  and  boulders  of  country  rock 
(residual  or  foreign) ;  (e)  change  with  depth ;  ( /)  change 
with  approach  to  country  rock ;  (gr)  transition  gradual  or 
abrupt. 

(2)  Physical  character:   (a)  Form — compact,  powder,  granular 

crystalline,  boulder,  gravel,  shot,  pisolitic,  oolitic,  con- 
cretionary, mammillary,  stalactitic,  etc.;  (b)  variation, 
vertically  and  horizontally. 

(3)  Grades  of  ore,  proportion  of  rock  and  waste. 

(4)  Analyses ;  secure  them  whenever  possible. 

130 


SCHEDULES  131 

4.  The  ore — continued. 

(5)  Genesis,  based  on  observation  and  inference :  (a)  Gossan  of 
sulphide  deposit ;  (6)  oxidation  or  metamorphism  of  car- 
bonate; (c)  weathered  outcrop  of  ferruginous  or  man- 
ganiferous  rock;  (d)  deposited  as  vein  filling,  replace- 
ment, impregnation,  or  precipitate  by  (1)  surface  or  (2) 
spring  waters;  (e)  geologic  age  of  deposit. 

5.  Conditions    affecting    mining:     (a)    Topography,    accessibility, 

transportation  facilities,  building  sites,  settling  basins,  dumps, 
etc. ;  (6)  supplies — timber,  water,  fuel,  power,  etc. ;  (c)  climatic 
conditions — rainfall  (amount  and  distribution),  working  season, 
etc. 

6.  Development  (openings):    (a)  Surface  pit  or  cut — size,  shape, 

depth,  etc. ;  (b)  shaft,  slope,  or  tunnel — size,  length,  depth, 
equipment;  (c)  buildings — washer,  drying  sheds,  storage, 
power  house,  etc. 

7.  Methods,  actual  or  practicable. 

(1)  Mining:   Hand  work,  power  shovel,  drilling,  blasting,  etc. 

(2)  Handling:  Hand  barrow,  tram  (surface  or  aerial),  conveyor, 

elevator,  chute  (with  or  without  water),  etc. 

(3)  Drainage,  timbering,  etc. 

(4)  Preparation  for  market :  (a)  Sorting,  hand  picking,  cobbing  ; 

(b)  screening — type  and  mesh;  (c)  washing — type,  ca- 
pacity; (d)  drying — air  or  furnace,  type,  capacity;  (e) 
average  cost  per  unit  product. 

8.  Disposition  of  ore. 

(1)  Uses:    (a)  For  metals — iron,  manganese,  aluminum;    (6) 

chemical  products;  (c)  pigments,  etc.;  (d)  fire  brick 
(bauxite). 

(2)  Markets:    (a)  Demand  and  supply;    (6)  competition;    (c) 

freight  rates. 

9.  Statistics. 

(1)  Date  of  opening  mine. 

(2)  Amount  and  value  of  (a)  average  annual  production ;   (b) 

production  for  last  calendar  year ;  (c)  total  production  to 
date. 

(3)  Estimate  of  tonnage  remaining  in  the  deposit. 

(4)  Royalties,  form  of  lease,  option,  value  of  land,  etc. 


SCHEDULE  8.     Stone 

A. SEDIMENTARY   ROCKS 

1.  Location:    (a)  Map  reference;    (6)  name  of  quarry;    (c)  nearest 

town   and    railroad    station,    distance;     (d)    name    and 
address  of  owner. 

2.  Petrology. 

(1)  Classification:  Scientific  and  trade  names. 

(2)  Detailed  sections,  noting  for  each  bed  (a)  thickness  and 

texture;  (6)  color — fresh  and  weathered;  (c)  banding, 
spotting,  mottling,  etc. 

(3)  Composition:    (a)  Essential  constituents,  form  and  size  of 

grains,  character  and  proportion  of  cement ;  (6)  accessory 
constituents,  especially  those  that  are  deleterious,  as 
pyrite,  etc.;  (c)  chemical  composition — analyses  by 
benches  or  average  of  quarry  face. 

(4)  Weathering:  (a)  Depth;  (6)  character  of  change ;  (c)  char- 

acter of  contact  between  weathered  and  un  weathered; 
(d)  character  of  surfaces  exposed  at  various  distances 
from  original  surface  for  determiniable  periods. 

(5)  Workability:  (a)  Hardness  and  toughness,  fresh  and  weath- 

ered; (6)  fracture;  (c)  ease  of  cutting — when  fresh  or 
seasoned,  with  or  across  bedding. 

3.  Geologic  relations. 

(1)  Stratigraphy:    (a)  Formation  names;    (6)  age;    (c)  asso- 

ciated rocks,  dikes,  etc. 

(2)  Structure. 

(I)  Of  the  general  region  (see  Schedule  3). 
(II)  In  the  quarry:  (a)  Dip,  strike;  (b)  unconformity, 
cross-bedding;  (c)  folding,  crumpling,  fracturing, 
or  faulting  of  beds ;  (d)  joints — systems,  spacing, 
direction,  filling,  motion,  alteration,  staining,  etc.; 
(e)  character  of  bedding  planes — smooth,  rough, 
clean,  clay  covered,  micaceous,  stylolitic,  etc. 

132 


SCHEDULES  133 

4.  Conditions  affecting  quarrying. 

(1)  Outcrops:    (a)  Form  and  extent;    (b)  relations  to  topog- 

raphy;   (c)  relations  to  bedding,  structure,  etc. 

(2)  Overburden :   (a)  Character ;   (6)  maximum,  minimum,  and 

average  thickness. 

(3)  Quantity  available:   Vertical  thickness  and  areal  extent 

of  formation. 

5.  Development. 

(1)  Quarry:    (a)  Date  of  opening;   (b)  type — sidehill,  pit;   (c) 

form  and  dimensions;  (d)  drainage. 

(2)  Quarrying  methods:   (a)  Stripping;   (b)  drilling;   (c)  blast- 

ing;  (d)  channeling;   (e)  splitting;   (/)  handling. 

(3)  Preparation  for  market :  Equipment  and  methods  for  saw- 

ing, planing,  dressing,  polishing,  crushing,  pulverizing, 
etc. 

6.  Utilization,  actual  and  possible. 

(1)  Products:    Dimensions,  rough  (riprap),  ballast,  flagging, 

curbing,  paving,  abrasive  (grindstones,  whetstones,  etc.), 
macadam,  concrete,  cement,  lime,  flux,  glass,  ganister, 
fertilizer,  etc. 

(2)  Sizes:  (a)  Obtained;  (b)  obtainable  (maximum). 

(3)  Tests  for  strength,  hardness,  absorption,  fire  resistance,  etc. 

(4)  Markets,  examples  of  structures  in  which  product  has  been 

used. 

(5)  Transportation:    (a)  Shipping  point;    (b)  haulage  to  ship- 

ping point ;  (c)  mode  of  transportation  to  market. 

7.  Costs  and  prices. 

(1)  Quarrying:   (a)  Average  cost  per  unit  quantity;  (6)  wages 

of  unskilled  laborers. 

(2)  Preparation  for  market:  Cost  per  unit  for  sawing,  dressing, 

polishing,  crushing,  etc. 

(3)  Transportation  to  market,  freight  rates. 

(4)  Prices  f.o.b.:  Average  for  various  products  and  grades. 

8.  Statistics :  Quantity  and  value  of  (a)  average  yearly  production ; 

(b)  production  for  last  calendar  year ;    (c)  total  production 
to  date. 


134  INSTRUCTIONS    FOR    SPECIAL    INVESTIGATIONS 

B. IGNEOUS   ROCKS 

1.  Location:    (a)  Map  reference;    (b)  name  of  quarry;    (c)  nearest 

town  and  railroad  station ;   (d)  name  and  address  of  owner. 

2.  Petrology. 

(1)  Classification:    (a)  Specimen  numbers;    (6)  scientific  and 

trade  names. 

(2)  Microscopic  characters:    (a)  Essential  minerals;   (6)  acces- 

sory minerals,  especially  such  as  are  deleterious,  as 
pyrite,  etc.;  (c)  texture  or  grain — crypto  or  coarse  crys- 
talline, porphyritic,  vitreous,  etc. ;  (d)  secondary  changes 
due  to  replacements,  contacts  with  dikes,  etc. ;  (e)  inclu- 
sions, segregations,  veins,  etc. 

(3)  Workability:     (a)    Hardness   and   toughness — fresh    and 

weathered ;  (b)  fracture ;  (c)  ease  of  cutting — when  fresh 
or  seasoned,  with  or  across  foliation. 

(4)  Weathering :   (a)  Depth ;  (b)  character  of  change ;  (c)  char- 

acter of  contact  between  weathered  and  un weathered: 
(d)  character  of  surfaces  exposed  at  various  distances 
from  original  surface  for  determinable  periods. 

3.  Geologic  relations. 

(1)  Stratigraphy:  (a)  Formation  name ;  (fr)age;  (c)  associated 

sedimentary  or  igneous  rocks,  dikes,  etc. 

(2)  Structure:    (a)  Joints — systems,  spacing,  direction,  filling, 

motion,  alteration,  staining,  etc.;,  (b)  rift,  foliation, 
sheets,  planes  of  separation — character,  extent,  direc- 
tion; (c)  exfoliation;  (d)  dikes — character,  size,  direc- 
tion, etc. 

4.  Conditions  affecting  quarrying. 

(1)  Outcrops:    (a)  Form  and  extent;    (b)  relations  to  topog- 

raphy;   (c)  relations  to  structure. 

(2)  Overburden:   (a)  Character;   (b)  maximum,  minimum,  and 

average  thickness. 

(3)  Quantity  available. 

5.  Development. 

(1)  Quarry:   (a)  Date  of  opening ;  (b)  type — sidehill  or  pit ;  (c) 

form  and  dimensions ;  (W)  drainage. 

(2)  Quarrying  methods :   (a)  Stripping ;   (6)  drilling ;   (c)  blast- 

ing; (d)  channeling;  (e)  splitting — pneumatic  and  hy- 
draulic; (/)  handling. 


SCHEDULES  135 

5.  Development — Continued. 

(3)  Preparations  for  market ;  equipment  and  method  for  dress- 
ing, polishing,  crushing,  etc. 

6.  Utilization,  actual  and  possible. 

(1)  Products:  Ornamental,  dimension,  rough  (riprap),  ballast, 

macadam,  concrete,  etc. 

(2)  Sizes:  (a)  Obtained;  (6)  obtainable  (maximum). 

(3)  Tests  for  specific  gravity,  strength,  absorption,  fire-resist- 

ance, etc. 

(4)  Markets ;  examples  of  structures  in  which  product  has  been 

used. 

(5)  Transportation:    (a)  Shipping  point;    (6)  haulage  to  ship- 

ping point ;  (c)  mode  of  transportation  to  market. 

7.  Costs  and  prices. 

(1)  Quarrying:    (a)  Average  cost  per  unit;    (b)  wages  of  un- 

skilled laborers. 

(2)  Preparation  for  market :  Cost  per  unit  for  dressing,  polish- 

ing, crushing,  etc. 

(3)  Transportation  to  market ;  freight  rates. 

(4)  Price  f.o.b. :  Average  for  various  products  and  grades. 

8.  Statistics :  Quantity  and  value  of  (a)  average  yearly  production ; 

(6)  production  for  last  calendar  year ;   (c)  total  production 
to  date. 


SCHEDULE  9.     Road  materials 


1.  Location:    (a)  Map  reference;    (b)  nearest  town  and  railroad 

station,  distance ;  (c)  name  and  address  of  owner. 

2.  Petrology:    (a)  Sample  number;    (b)  trade  and  scientific  names; 

(c)  maximum,  minimum,  and  average  coarseness  of  grain ;   (c?} 
texture;    (e)  color;    (/)  uniformity;    (g)  alterations. 

3.  Geologic  relations. 

(1)  Stratigraphy:    (a)  Formation  names;    (b)  age;    (c)  asso- 

ciated rocks,  dikes,  etc. ;  (d)  photograph  or  sketch  show- 
ing relations. 

(2)  Structure:    (a)  Massive  or  bedded;   (b)  fissility;   (c)  folds; 

(d)  fractures;  (e)  rift. 

4.  Conditions  affecting  quarrying. 

(1)  Outcrops:    (a)  Form  and  extent;    (b)  relations  to  topog- 

raphy, bedding,  structure,  etc. 

(2)  Overburden :  (a)  Character ;  (b)  maximum,  minimum,  and 

average  thickness. 

(3)  Quantity  available:  Approximate  cubic  yards.  , 

5.  Development. 

(1)  Quarry:   (a)  Date  of  opening ;  (6)  number  of  openings ;  (c) 

form  and  dimensions;  (d)  drainage. 

(2)  Quarrying  methods:    (a)  Number  and  kind  of  drills;    (b) 

method  of  blasting;  (c)  handling. 

(3)  Preparation  for  market :   (a)  Number  and  kind  of  crushers  ; 

(6)  sizes  of  crushed  material  produced ;  (c)  percentage  of 
each;  (d)  kinds  of  screens;  (e)  storage  facilities;  (/) 
weight  per  cubic  yard  crushed. 

6.  Utilization. 

(1)  Shipment:    (a)  Shipping  point;    (b)  haulage  to  shipping 

point ;  (c)  mode  of  transportation. 

(2)  Uses:    (a)  Principal  markets;    (b)  examples  of  roads  con- 

structed of  this  material;  (c)  names  and  addresses  of 
those  in  charge  of  construction  and  maintenance  of  these 
roads;  (d)  quality  of  such  roads. 

136 


SCHEDULES  137 

7.  Costs  and  prices :   (a)  Average  cost  per  cubic  yard  of  quarrying ; 

(6)  of  crushing ;  (c)  average  prices  of  various  grades  produced ; 
f.o.b.  quarry;   (d)  wages  of  unskilled  laborers. 

8.  Statistics :  Quantity  and  value  of  (a)  average  yearly  production  ; 

(b)  production  for  last  calendar  year ;   (c)  total  production  to 
date. 

9.  Tests:  (a)  Results;  (6)  by  whom  made. 

10.  Soils,  character  of,  in  neighborhood. 

11.  Other  materials  available  in  district  for  road  construction. 


B. GRAVEL 

1.  Location:  (a)  Map  reference;  (6)  nearest  town  and  railroad  sta- 

tion, distance;   (c)  name  and  address  of  owner. 

2.  Physical  and  petrographic  character:    (a)  Maximum,  minimum, 

and  average  size  of  pebbles ;  (6)  are  pebbles  angular  or  round  ; 
(c)  kinds  of  rock  constituting  pebbles;  (d)  approximate  per- 
centage of  each;  (e)  character  of  matrix;  (/)  proportion  to 
pebbles ;  (g)  presence  or  absence  of  stratification ;  (h)  dip ;  (i) 
clay  streaks  or  pockets ;  (/)  do  walls  of  pit  overhang  or  stand 
up  well;  (k)  uniformity  of  deposit. 

3.  Geologic  relations:    (a)  Age;   (b)  origin;   (c)  associated  surficial 

deposits;    (d)  relations  to  neighboring  hard-rock  masses;   (e) 
to  what  extent  are  the  gravels  derived  therefrom ;  ( /)  photo- 
graph or  sketch  showing  relations. 
4.  Conditions  affecting  development. 

(1)  (a)  Form  and  extent  of  deposit ;  (6)  relation  to  topography. 

(2)  Overburden :  (a)  Character ;  (6)  maximum,  minimum,  and 

average  thickness. 

(3)  Approximate  quantity  available,  in  cubic  yards. 
5.  Development. 

(1)  Pit:    (a)  Date  of  opening;   (6)  form  and  dimensions;   (c) 

drainage. 

(2)  Excavating:    (a)  Mechanical  excavators — number,  kind, 

and  capacity;  (b)  method  of  transporting  at  pit. 

(3)  Preparation   for  market,   mechanical   devices  used  for 

handling  and  storing  material. 


138  INSTRUCTIONS    FOR  SPECIAL    INVESTIGATIONS 

6.  Utilization. 

(1)  Shipment:    (a)  Shipping  point;    (ft)  haulage  to  shipping 

point;  (c)  mode  of  transportation. 

(2)  Uses:    (a)  Principal  markets;    (b)  examples  of  roads  con- 

structed of  this  material ;  (c)  names  and  addresses  of 
those  in  charge  of  construction  and  maintenance  of  these 
roads;  (d)  quality  of  such  roads. 

7.  Costs  and  prices :  (a)  Average  cost  per  cubic  yard  for  excavating  ; 

(6)  cost  of  crushing,  screening,  etc. ;  (c)  price  of  material  f.o.b. 
nearest  shipping  point ;   (d)  wages  of  unskilled  laborers. 

8.  Statistics :  Quantity  and  value  of  (a)  average  yearly  production  ; 

(6)  production  for  last  calendar  year ;   (c)  total  production  to 
date. 

9.  Soil,  character  of,  in  neighborhood. 

10.  Other  materials  available  in  district  for  road  construction. 


SCHEDULE  10.     Cement  materials  and  lime 

1.  Location:   (a)  Map  reference  or  description;   (b)  name  of  quarry, 

pit,  property,  or  claim;    (c)  names  and  addresses  of  owner 
superintendent. 

2.  Material. 

(1)  Class:   (a)  Natural  cement  rock;  (b)  limestone;   (c)  chalk; 

(d)  marl;  (e)  shale;  (/)  clay. 

(2)  Lithology:    (a)  Mineralogical  composition;    (b)  chemical 

composition  and  specific  gravity  (obtain  analyses  if  pos- 
sible) ;  (c)  uniformity;  (d)  physical  character,  color,  frac- 
ture, hardness,  etc.;  (e)  visible  impurities,  chert  nodules, 
sand  grains,  and  pebbles ;  ( f)  beds  or  portions  of  deposit 
rejected — cause . 

3.  Geologic  relations. 

(1)  Stratigraphy:    (a)  Formation  name;    (b)  age;   (c)  position 

within  the  formation. 

(2)  Structure:   Bedding,  dip,  strike,  faulting,  jointing,  folding, 

etc. 

(3)  Origin  (clay) :  Residual,  alluvial,  glacial,  sedimentary,  etc. 

4.  Conditions  affecting  development. 

(1)  Outcrops:  (a)  Form  and  extent ;  (b)  relation  to  topography 

and  drainage. 

(2)  Overburden:     (a)    Character;     (b)   thickness — maximum, 

minimum,  and  average. 

(3)  Quantity  available:  Vertical  and  areal  dimensions. 

(4)  Accessiblity,  transportation,  timber,  water,  etc. 

(5)  Fuel  supply:  Kind  and  cost. 

5.  Development. 

(1)  Quarry,  pit,  or  mine:  (a)  Type;  (6)  date  opened;  (c)  form 

and  dimensions. 

(2)  Methods  of  quarrying  or  excavating:    (a)  Stripping;    (b) 

drilling;  (c)  blasting;  (d)  dredge  or  power  shovel;  (e) 
draining;  (/)  timbering. 

(3)  Methods  of  handling:    (a)  Wheelbarrow;  (6)  tramway;  (c) 

conveyor,  elevator,  etfc. 

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140  INSTRUCTIONS    FOR   SPECIAL    INVESTIGATIONS 

5.  Development — Continued. 

(4)  Preparation:    (a)  Crushing;    (b)  drying;    (c)  grinding — 

type,  fineness,  etc. ;    (d)  mixing — local  or  foreign  mate- 
rial, source  of  gypsum;  (e)  proportions. 

(5)  Equipment  for  excavating,  handling  and  preparing  mate- 

rial, and  unit  costs. 

(6)  Burning:   (a)  Kilns — date  of  erection,  type,  size,  capacity; 

(6)  fuel — kind  and  method  of  use. 

(7)  Cooling  and  seasoning  of  clinker. 

(8)  Grinding  clinker. 

(9)  Hy  drat  ing  lime. 

6.  Product:   (a)  Natural  cement;   (6)  Portland  cement-   (c)  lime. 

(1)  Brands  and  trade  name. 

(2)  Packing:  Barrels,  bags,  or  bulk. 

(3)  Markets:    (a)  Location  and  competing  supply;    (6)  trans- 

portation ;  (c)  freight  rates. 

7.  Statistics:  Amount  and  value  of  (a)  average  annual  production^ 

(&)  production  for  last  calendar  year, 


SCHEDULE  11.     Clay 

1.  Location:    (a)  Map  reference  or  description;    (b)  name  of  pit, 

mine,  or  property;   (c)  name  and  address  of  owner. 

2.  Character  of  exposure :   (a)  Natural  outcrop ;   (b)  pit  or  mine ;   (c) 

extent,  horizontally  and  vertically. 

3.  Detailed  sections,  noting  for  each  bed — 

(1)  Physical  character:    (a)  Thickness  ;  (6)  color — oxidized  01 

unoxidized,  surface  stain,  mottling,  banding,  etc.;  (c) 
texture;  (d)  fracture;  (e)  hardness;  (/)  slacking;  (</) 
plasticity. 

(2)  Composition :   (a)  Essential  constituents — analyses  of  sepa- 

rate beds  or  entire  face;  (6)  visible  impurities,  sand 
grains  (material),  concretions  (character  and  composi- 
tion), boulders,  vegetable  matter,  etc. 

4.  Geologic  relations. 

(1)  Stratigraphy:  (a)  Formation  name  and  age ;  (b)  position  in 

the  formation ;    (c)  relation  to  adjoining  rocks. 

(2)  Structure:  Dip,  strike,  faulting,  jointing,  etc. 

(3)  Origin:    (a)  Residual  mantle  from  removal  of  soluble  por- 

tion of  argillaceous  rock ;  (6)  residual  deposit  from  decay 
of  feldspathic  dike  or  other  rock  mass ;  (c)  sedimentary, 
evenly  stratified  by  deposition  in  standing  water;  (d) 
alluvial,  stream  laid;  (e)  glacial,  unmodified  drift. 

5.  Conditions  affecting  development. 

(1)  Outcrops:  (a)  Form  and  extent ;  (b)  relation  to  topography 

and  drainage;    (c)  relation  to  bedding,  structure,  etc. 

(2)  Overburden:     (d)    Character;     (b)   thickness — maximum, 

minimum,  and  average. 

(3)  Quantity  available:  Vertical  and  areal  dimensions. 

(4)  Accessibility,  supplies  of  timber,  water,  fuel,  etc. 

(5)  Association  with  deposit  of  other  mineral  mined:  Coal, 

iron  ore,  bauxite,  mica,  etc. 

6.  Development. 

(1)  Pit  or  mine:    (a)  Date  opened;    (b)  type;    (c)  form  and 
dimensions. 

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142  INSTRUCTIONS  FOR   SPECIAL   INVESTIGATIONS 

6.  Development — Continued. 

(2)  Mining  methods:   (a)  Stripping;   (6)  drilling;   (c)  blasting; 

(d)  power  shovel;   (e)  drainage;   (/)  timbering. 

(3)  Handling:   (a)  Wheelbarrow;   (b)  tramway;   (c)  conveyor, 

etc. 

(4)  Preparation :  (a)  Grinding — type  of  machines,  fineness ;  (b) 

mixing — local  or  foreign  material ;  (c)  washing ;  (d)  pug- 
ging; (e)  drying  (air  or  furnace — type);  (/)  drying 
shrinkage;  (g)  storage. 

(5)  Equipment  for  mining,  handling,  and  preparing  product. 

7.  Utilization  at  or  near  point  of  production. 

(1)  Products:    (a)  Structural  material — brick,  tile,  etc.;    (b) 

pottery,  stoneware,  drain  tiles,  etc. 

(2)  Equipment  and  methods  of  molding. 

(3)  Burning:    (a)  Kilns — type,  capacity;    (b)  fuel;    (c)  distri- 

bution of  heat  and  temperature ;  (d)  length  of  burn ;  (e) 
burning  shrinkage. 

(4)  (a)  Grades — capacity  and  output  of  each  for  calendar  year ; 

(b)  prices;  (c)  markets;  (d)  shipping  facilities;  (e) 
freight  rates. 

8.  Shipping  raw  products :  (a)  Uses ;  (b)  markets ;  (c)  transportation 

facilities  and  freight  rates;  (d)  prices  at  mine. 


SCHEDULE  ±2.     Sand  and  gravel 

1.  Location:    (a)  Map  reference  or  description;    (b)  name  of  pit, 

bank,  or  property ;  (c)  name  and  address  of  owner. 

2.  Character  of  deposit ;  make  sketches  and  sections. 

(1)  Composition:     (a)   Minerals  composing  sand  grains;    (b) 

rocks   composing   pebbles;     (c)    proportion   of   various 
mineral  and  rock  types;   (d)  pebbles  fresh  or  decayed. 

(2)  Size :    (a)  Of  sand  grains ;   (b)  of  pebbles ;   (c)  of  boulde  rs ; 

(d)  proportion  of  each. 

(3)  Shape  (rounded,  polished,  angular,  subangular):    (a)   Of 

sand  grains;  (b)  of  pebbles;  (c)  of  boulders. 

(4)  Induration :    (a)  By  pressure ;   (b)  by  cementation — nature 

of  cement ;  (c)  by  clay  binder. 

(5)  Structure  of  deposit:  (a)  Stratified ;  (b)  massive;  (Across- 

bedded  ;  (d)  pebbles  imbricated. 

(6)  Rejected  material :  (a)  Stratified  clay  beds ;  (b)  clay  lenses ; 

(c)  clay  lumps,  balls,  etc.;    (d)  peat  layers;    (e)  logs, 
stumps,  roots,  etc. 

3.  Geologic  relations. 

(1)  Origin:    (a)  Agency  forming  deposit  (see  Schedule  4);  (b) 

source  of  material. 

(2)  Age,  stratigraphic  and  physiographic  relations  (see  Sched- 

ule 1). 

(3)  Relations  to  associated  hard-rock  formations. 

4.  Conditions  affecting  development. 

(1)  Outcrops:  (a)  Form  and  extent ;  (b)  relation  to  topography 

and  drainage ;  (c)  accessibility. 

(2)  Overburden:   (a)  Character;  (6)  maximum,  minimum,  and 

average  thickness. 

(3)  Water:  (a)  Distribution;  (b)  amount;  (c)  drainage. 

(4)  Amount  available. 

5.  Development. 

(1)  Pit  or  bank:  (a)  Date  of  opening ;  (b)  form  and  dimensions ; 

(c)  drainage. 

(2)  Stripping. 

143 


144  INSTRUCTIONS   FOR    SPECIAL    INVESTIGATIONS 

5.  Development — Continued. 

(3)  Excavating:    (a)  By  hand;    (b)  mechanical  excavators — 

number,  kind,  capacity. 

(4)  Handling:    (a)  Wheelbarrow;    (b)  tram;    (c)  conveyor — • 

kind,  capacity. 

(5)  Preparation  for  market :   (a)  Screening,  crushing,  washing, 

drying;  (b)  methods  and  equipment ;  (c)  storage. 

(6)  Cost  per  unit,  when  obtainable. 

6.  Uses,  actual  or  possible. 

(1)  Structural:  Mortar,  plaster,  concrete,  roofing,  walls  (boul- 

ders), etc. 

(2)  Glass  (get  analyses). 

(3)  Abrasive:  Stone  sawing,  polishing,  etc. 

(4)  Traction:  Locomotive,  trolley,  etc. 

7.  Markets:    (a)  Location;   (b)  transportation  facilities;    (c)  freight 

rates. 

8.  Statistics:  Amount  and  value  of  various  grades  (a)  produced  in 

last  calendar  year;  (b)  produced  to  date. 


SCHEDULE  13.     Coal 

1.  Location:    (a)  Map  reference;    (b)  name  of  mine  or  prospect; 

(c)  name  and  address  of  owner  or  operator  and  mine  superin- 
tendent. 

2.  Geologic  relations. 

(1)  Exposure:   (a)  Kind — outcrop,  prospect,  mine ;  (6)  relation 

to  topography. 

(2)  Formation :   (a)  Name ;  (b)  age ;  (c)  position  of  coal  bed  in 

the  formation;  (d)  petrology  (see  Schedule  2). 

(3)  Structure  of  the  region  (see  Schedule  3). 

(4)  Drill  records ;  copy  all  available  and  get  map  locations. 

3.  Coal  bed ;  make  numerous  detailed  measured  sections,  observing 

and  noting — 

(1)  Roof:     (a)   Material;     (b)   thickness;     (c)    character  and 

strength;  (d)  draw  slate;  (e)  any  conditions  affecting 
ease  or  safety  of  mining. 

(2)  Coal:    (a)  Kind — anthracite,  bituminous,  subbituminous, 

lignite,  cannel,  splint,  etc. ;  (b)  character  and  appear- 
ance— color,  luster,  texture,  fracture,  hardness,  cleat 
(direction  of  faces  and  butts),  effect  of  weathering,  lia- 
bility to  spontaneous  combustion,  etc.;  (c)  bedded 
impurities  (partings  and  binders) — character,  thickness, 
position,  loose  or  adhesive,  taken  or  rejected  in  mining; 
(d)  other  impurities  (sulphur  balls,  calcite,  etc.) — kind, 
abundance,  distribution,  ease  of  separation,  etc.;  (e) 
irregularities  and  their  effects  on  mining — rolls,  horse- 
backs, clay  veins,  faults,  wants,  dikes,  etc. 

(3)  Floor:    (a)   Material;    (b)  thickness;    (c)   character;    (d) 

tendency  to  heave;  (e)  adaptability  to  mining;  (/) 
containing  stems  and  roots. 

(4)  Collect  (a)  coal  samples  (see  directions,  pp.  75-78);    (6) 

fossils,  especially  in  roof  and  on  dump. 

4.  Conditions  affecting  mining. 

(1)  Topography,  accessibility,  transportation  facilities,  build- 

ing sites,  dumps,  etc. 

(2)  Supplies — timber,  water,  power,  etc. 

(3)  Climatic  conditions,  working  season,  etc. 

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146  INSTRUCTIONS   FOR   SPECIAL  INVESTIGATIONS 

5.  Development  (make  sketches  and  photographs). 

(1)  Surface  equipment :   (a)  Buildings;  (6)  hoist;   (e)  trackage, 

tipple,  bins,  etc. 

(2)  Mine  equipment:    (a)  Shaft — size,  depth,  compartments, 

etc.;   (6)  incline — slope,  direction,  length,  depth,  equip- 
ment; (c)  tunnel — length,  size,  etc. 

(3)  Workings:   (a)  General  plan  (get  mine  map),  room  and  pil- 

lar, long  wall;  (b)  size  of  rooms,  pillars,  gangways,  etc. 

6.  Methods. 

(1)  Mining:    (a)  Under  cut,  sheared,   shot  from  solid,  etc.; 

(6)  hand  or  machine  (type) ;   (c)  kind  of  power,  kind  of 
explosive. 

(2)  Handling  coal  in  mine :   (a)  Type — mule,  rope,  motor ;  (6) 

power. 

(3)  Timbering:  Amount  and  kind  required. 

(4)  Drawing  pillars. 

(5)  Ventilation:     (a)  Type — natural,  furnace,  fan;    (b)  gas; 

(c)  dust;  (d)  liability  to  explosion. 

(6)  Drainage :   (a)  Type ;   (6)  plant ;   (c)  amount  of  water  pres- 

ent. 

7.  Preparation  of  coal  for  market. 

(1)  Sizing:  (a)  Sizes  produced ;  (b)  percentage  of  each ;  (c)  kind 

of  screen. 

(2)  Cleaning:   (a)  In  mine;   (b)  picking;   (c)  washing. 

(3)  Handling:    (a)  Mechanical  loaders;   (6)  storage — kind  and 

capacity. 

8.  Utilization,  actual  and  possible. 

(1)  Uses:  (a)  Steam;  (6)  domestic;  (c)gas;  (d)  coking — loca- 

tion, number  and  type  of  ovens. 

(2)  Markets,  transportation  facilities,  freight  rates. 

(3)  Waste:  ^(a)  Benches  unmined;    (b)  pillars  not  drawn;   (c) 

slack  not  used. 

9.  Statistics. 

(1)  Value:    (a)  Coal  land;    (b)  royalties  (system  of  leasi  g), 

(c)  options. 

(2)  Production :  Quantity  and  value  of  (a)  average  yearly  pro- 

duction ;  (b)  production  for  last  calendar  year ;   (c)  total 
production  to  date. 


SCHEDULE  14.     Oil  and  gas  (well  data) 

1.  Location:    (a)  Map  reference  or  accurate  description;    (6)  name 

of  claim,  farm,  or  lease  and  designation  of  well;  (c)  names 
and  addresses  of  owner,  superintendent,  contractor,  driller; 
(d)  date  of  visit. 

2.  Geologic  relations. 

(1)  Formation  at  surface:    (a)  Name;    (6)  age;    (c)  lithologic 

character;  (d)  position  in  the  formation. 

(2)  Structure:   Relation  to  determined  folds,  faults,  joint  sys- 

tems, etc. 

(3)  Topography. 

3.  Condition  of  well:    (a)  Productive;   (b)  exhausted;   (c)  dry  hole; 

(d)  drilling. 

4.  Well  log:   if  possible  make  complete  copy,  which  should  show — 

(1)  Elevation  of  ground  or  top  of  casing. 

(2)  Dates:  (a)  Began  drilling;  (b)  finished  drilling. 

(3)  Depth  and  thickness  of  each  distinct  set  of  beds  penetrated 

and  distinguished  by  the  driller  (state  method  of  meas- 
urement— cable  or  wire). 

(4)  Lithologic  character:   (a)  Color,  hard  or  soft,  coarse  or  fine, 

pebbly,  fossiliferous,  sticky,  tough  or  brittle,  caving,  etc. ; 
(b)  effect  on  bits;  (c)  examine  samples  if  possible;  (d) 
determine  meaning  of  terms  used  by  driller. 

(5)  Horizons  yielding  oil,  gas,  tar,  water,  dry  rock :  Depth  and 

thickness;  temperature  at  various  horizons. 

(6)  Product:  Kind  and  quality. 

(7)  Name  of  productive  stratum,  local  and  geologic. 

5.  Well  record. 

(1)  Yield  or  pressure:    (a)  When  first  tapped  (open,   closed, 

minute) ;  (6)  after  shooting ;  (c)  after  equilibrium  estab- 
lished; (d)  at  time  of  visit. 

(2)  Variation  in  pressure  related  to  variation  in  other  wells  in 

same  pool  (indicating  open  communication  or  otherwise) 
and  distance  to  other  wells  compared. 

(3)  Variation  in  gravity  of  oil  and  comparison  with  gravity  in 

other  wells  in  same  pool. 

147 


148  INSTRUCTIONS    FOR   SPECIAL   INVESTIGATIONS 

6.  Product. 

(1)  Gas:  Analyses  and  tests. 

(2)  Oil:  (a)  Color;  (6)  odor;  (c)  gravity. 

(3)  Oil  and  water:  (a)  Proportions;  (6)  fresh  or  salt  water. 

(4)  Water:  (a)  Fresh  or  salt;  (6)  capacity;  (c)  head. 

(5)  Other  substances:  Sand,  gypsum,  sulphur,  etc. 

7.  Methods. 

(1)  Drilling:   (a)  Kind  of  rig;   (6)  special  difficulties;   (c)  unit 

cost. 

(2)  Casing:    (a)  Kind;   (6)  sizes;   (c)  lengths  of  various  sizes; 

(d)  cost. 

(3)  Packing:  (a)  Kind;  (6)  purpose. 

(4)  Shooting:    (a)  Date;   (6)  explosive — quantity;   (c)  effect. 

(5)  Pumping:    (a)  Kind  of  pump;    (6)  power;    (c)  cost  per 

barrel. 

(6)  Storage:  (a)  Tanks — kind;  (6)  reservoirs;  (c)  capacity. 

(7)  Separating  oil  from  water  and  sludge. 

8.  Disposition  of  product. 

(1)  Markets:  Price  (a)  of  oil;   (fr)  of  gas — to  pipe  line,  to  con- 

sumer, sold  by  meter  or  flat  rate. 

(2)  Uses:    (a)  Refining — proportion  of  various  products;    (6) 

fuel ;  (c)  manufacture  of  gas ;  (d)  lubricating. 

(3)  Transportation:    (a)  Pipe  line — name  of  owner;    (6)  rail- 

road; (f)  water;  (d)  rates. 

9.  Statistics  of  single  well  or  group  of  wells  in  same  ownership  and 

pool:    Amount  and  value  (a)  of  production  for  last  calendar 
year;  (6)  of  total  production  to  date. 

10.  History  of  discovery  and  development  of  pool. 


APPENDIX  I 


THE  following  list  of  official  surveys  corrected  to  date,  Feb- 
ruary, 1909,  is  inserted  especially  for  the  convenience  of  those 
who  wish  to  secure  information,  published  or  unpublished,  relating 
to  the  geology  of  any  part  of  North  America. 

United  States  Geological  Survey,  Washington,  D.  C. 

Organized:  1879.  George  Otis  Smith,  Director.  Geologic 
Branch,  C.  W.  Hayes,  Chief  Geologist.  (About  150  persons 
regularly  employed  on  the  scientific  force  in  this  Branch.) 
Topographic  Branch,  R.  B.  Marshall,  Chief  Geographer. 
Water  Resources  Branch,  M.  O.  Leighton,  Chief  Hydrographer. 
Technologic  Branch,  J.  A.  Holmes,  Expert  in  Charge. 

Publications:  Annual  Reports,  1-29;  Monographs,  1-50;  Geo- 
logic Folios,  1-163;  Professional  Papers,  1-65;  Bulletins,  1-376; 
Water  Supply  Papers,  1-230;  Mineral  Resources,  1882-1907. 

STATE  GEOLOGICAL  SURVEYS 

Alabama.     Geological  Survey  of  Alabama,  University,  Ala. 
Organized:    1873.     Dr.  Eugene  A.  Smith,  State  Geologist. 
Publications:    Geological  map  of  Alabama,    1894;    Reports  of 
Progress,    1873-1888;     Bulletins,    1-9,    1886-1907;     Separate 
publications. 

Arkansas.     Geological  Survey  of  Arkansas,  Fayetteville,  Arkansas. 
Organized:    1907.     Prof.  A.  H.  Purdue,  State  Geologist. 
Publications : 

149 


150  APPENDIX    I 

Colorado.     State  Geological  Survey,  Boulder,  Colorado. 
Organized:  1907.     Prof.  R.  D.  George,  Director. 
Publications : 
California.      California    State    Mining    Bureau,     San    Francisco, 

Cal. 
Organized:    1880;   reorganized,  1893.     Lewis  E.  Aubury,   State 

Mineralogist. 

Publications:  Reports  (Annual  and  Biennial),  1880-1908 ;  Bulle- 
tins 1-53,  1888-1898;   Maps;   Register  of  Mines  and  Minerals, 
with  maps  (by  counties). 
Connecticut.   State  Geological  and  Natural  History  Survey,  Hartford, 

Conn. 

Organized:   1903.      Prof.  Wm.  North  Rice,  Middletown,    Super- 
intendent. 

Publications:   Bulletins  1-11,  1904-08. 

Florida.     Florida  State  Geological  Survey,  Tallahassee,  Florida. 
Organized:  1907.     E.  H.  Sellards,  State  Geologist. 
Publications:  Annual  Report,  1,  1907-08. 
Georgia.     Geological  Department  of  the  State  of  Georgia,  Atlanta, 

Ga. 

Organized:  1890.     S.  W.  McCallie,  State  Geologist. 
Publications:  Administrative  Report,  1890-1900;  Bulletins  1-17, 

1894-1908. 

Illinois.     State  Geological  Survey,  Urbana,  Illinois. 
Organized  1905.     Frank  W.  DeWolf,  Director 
Publications:    Administrative  Report,  1906-     ;   Geological  Map 
of  Illinois;    Bulletins  1-8,  1906-08  (includes  Yearbooks  1906- 
07) ;  Mineral  Production  of  Illinois,  1905-07. 
Indiana.     State  of  Indiana.     Department  of  Geology  and  Natural 

Resources,  Indianapolis,  Indiana. 

Organized:  1881.     Prof.  W.  S.  Blatchley,  State  Geologist. 
Publications:    Annual  Reports,   11-32,   1881-1907   (continuation 
of  1-10,  Annual  Reports  of  earlier  organization,   1869-78); 
Geological  Map  of  Indiana,  1893. 
Iowa.     Iowa  Geological  Survey,  Des  Moines,  Iowa. 
Organized:  1892.     Prof.  Samuel  Calvin,  Director. 
Publications:  Administrative  Reports,  1894-1905;  Bulletins  1-3, 
1901-06. 


APPENDIX    I  151 

Kansas.     State  University  Geological  Survey  of  Kansas,  Lawrence, 

Kans. 

Organized:  1894.     Prof.  Erasmus  Haworth,  State  Geologist. 
Publications:     Mineral    Resources    Bulletins,     1897-9—1902-3; 

(Reports  or  Monographs)  v.  1-8,  1896-1904. 
Kentucky.     Kentucky  Geological  Survey,  Lexington,  Kentucky. 
Organized:  1903.     Prof.  C.  J.  Norwood,  Director. 
Publications:  Bulletins  1-7,  1904-07;  Report  of  Progress,  1904-5 

—1905-6. 
Louisiana.     Geological  Survey  of  Louisiana. 

Organized:    1888.     Prof.  Gilbert  D.  Harris,  Geologist  in  Charge, 

Ithaca,  New  York,  Cornell  University. 
Publications:  Bulletins  1-6,  1905-07;  "  Geology  and  Agriculture," 

Pts.  1-6,  in  2  vols.,  1892-1902. 
Maryland.     Maryland  Geologic  and  Economic  Survey,  Baltimore, 

Md. 

Organized:  1896.     Prof.  Wm.  B.  Clark,  State  Geologist. 
Publications:   County  Reports  with  maps,  15  vols.;   (Monographs 
dealing  with  systematic  geology  of  Maryland,  Eocene,  Miocene, 
Pliocene,  and  Pleistocene) ;   (Reports),  v.  1-6,  8.     1897-1908. 
Michigan.     Geological  Survey  of  Michigan,  Lansing,  Michigan. 
Organized:    1838:    reorganized,  March  26,  1869.     Dr.  Alfred  C. 

Lane,  State  Geologist. 
Publications:  Reports  (4°)  v.  1-9,  1869-1904;  Reports  (Annual? 

of  the  State  Board  of  Geological  Survey,  1-9,  1899-1907. 
Mississippi.     Geological  Survey  of  Mississippi,  Biloxi. 
Organized:  1906.     A.  F.  Crider,  Director. 
Publications:  Bulletins  1-4,  1907-08. 

Missouri.     State  of  Missouri,  Bureau  of  Geology  and  Mines,  Rolla. 
Organized:    1889.     H.  A.  Beuhler,  Director  and  State  Geologist. 
Publications:    Biennial  Report  State  Geologist,  1889-1906;   Re- 
ports 1-13,   1891-1900;    2d  ser.,  v.  1-8,    1903-08;    Bulletins 
1-5,  1890-91. 
Nebraska.     Geological  Survey  of  Nebraska,  Lincoln. 

Organized:    1901.     Prof.  Erwin  H.  Barbour,  State  Geologist. 
Publications:    Reports,   v.    1-2,    1903-07;    Reports   1890-1901, 
included  in  Annual  Keports  Nebraska  State  Board  of  Agri- 
culture. 


152  APPENDIX    I 

New  Jersey.     Geological  Survey  of  New  Jersey,  Trenton. 
Organized:   1863.     Dr.  H.  B.  Kiimmel,  State  Geologist. 
Publications:     Annual    Reports,     1863-1907;     Final    Reports, 
vol.  1-6,  1888-1904;  Atlas  of  New  Jersey ;  Report  on  Paleon- 
tology, vol.  1-4,  1886-1907. 

New  York.     New  York  State  Education  Department,  Science  Divi- 
sion, Albany,  N.  Y.  State  Museum. 
Organized:     1883;    reorganized,    1904.     Dr.    John    M.    Clarke, 

Director  and  State  Geologist. 
Publications:     Report   of   State   Geologist,    1-27,    1881-1907; 

Memoirs. 
North  Carolina.     North  Carolina  Geological  and  Economic  Survey, 

Chapel  Hill. 

Organized:  1891.     Dr.  Joseph  Hyde  Pratt,  Director. 
Publications:    Biennial  Reports,  1891-1904;   Bulletins,  1-17,  19, 
1891-1908;   Economic  Papers  1-14,  1897-1907;   Reports  1-2, 
1905-07. 
North    Dakota.       North     Dakota    Geological     Survey.       Grand 

Forks. 

Organized:    1899.     Dr.  A.  G.  Leonard,  State  Geologist. 
Publications:  Biennial  Report  1-4,  1899-1906. 
North  Dakota.     Agricultural  and  Economic  Geological  Survey  of 

North  Dakota,  Agricultural  College. 
Organized:  1901.     Prof.  Daniel  E.  Willard,  Director. 
Publications:   Biennial  Reports  1-3,  1901-06. 
Ohio.     Ohio  Geological  Survey,  Columbus. 

Reorganized:    1900.      Prof.  John  A.  Bownocker,   State  Geolo- 
gist. 

Publications:  Bulletins  1-9,  1903-08. 
Oklahoma.  Oklahoma  Geological  Survey,  Norman. 
Organized:  1908.     Charles  N.  Gould,  Director. 
Publications:  Bulletin  1,  1908;  Circular  1,  1908. 
South  Carolina.     South  Carolina  Geological  Survey,  Charleston. 
Organized:  1902.     Dr.  Earle  Sloan,  State  Geologist. 
Publications:  Bulletin  (4th  ser.),  No.  1-2,  1904-08. 
South  Dakota.     South  Dakota  Geological  Survey,  Vermilion. 
Organized:  — .     Prof.  E.  C.  Perisho,  State  Geologist. 
Publications:  Bulletins  1-3,  1894-1902. 


APPENDIX   I  153 

Vermont.     Geological  Survey  of  Vermont,  Burlington. 

Organized:    1896;   reorganized,  1900.     Prof.  George  H.  Perkins, 

State  Geologist. 

Publications:    Biennial  Reports  1-6,  1898-1908. 
Virginia.     Virginia  Geological  Survey,  Charlottes ville. 
Organized:    1904.     Prof.  Thomas  L.  Watson,  State  Geologist. 
Publications:  Bulletins  1-3,  1905-06. 
Washington.     Washington  Geological  Survey,  Seattle. 

Organized:    1901.     Prof.  Henry  Landes,  State  Geologist. 
Publications:  Annual  Report  of  State  Geologist,  1901-02,  2  vols.; 
Biennial  Reports  Board  of  Geological  Survey,  1901—03,  1  vol. 
West  Virginia.     West  Virginia  State  Geological  and  Economic  Sur- 
vey, Morgantown. 

Organized:  1897.     Prof.  I.  C.  White,  State  Geologist. 
Publications:  Report  1897-98;  Biennial  Report  1901-02,  1  vol.; 
Bulletin  1,  1901;   (Economic  Reports),  1,  IA,  2,  2A,  3,  1899- 
1908. 
Wisconsin.     State  of  Wisconsin   Geological  and   Natural   History 

Survey,  Madison. 
Reorganized:     1897.     (First    Survey,    1853-1879.)     Dr.    E.    A. 

Birge,  Director. 

Publications:   Biennial  Reports  1-5,  1897-1906:   Bulletins  1-20, 
1898-1908;   Hydrographic  maps;   Road  Pamphlets  1-4,  1907. 
Wyoming.     Wyoming  Geological  Survey,  Cheyenne. 
Organized:  1901.     Henry  C.  Beeler,  State  Geologist. 
Publications:    Reports  1903-06,  2  vols.;    Wyoming  Mines  and 
Minerals,  1907. 


CANADIAN  SURVEYS 

Canada. — Department  of  Mines,  Geological  Survey  Branch,  Ottawa. 

Organized:  1842.  R.  W.  Brock,  Director;  Joseph  Whiteaves, 
Assistant  Director  and  Paleontologist ;  John  Macoun,  Assistant 
Director  and  Naturalist;  Clovis  O.  Senecal,  Geographer  and 
Chief  Draughtsman. 

Publications:  Annual  Reports,  1842-date;  Maps;  Miscel- 
laneous publications. 


154  APPENDIX   I 

Ontario.     Bureau  of  Mines,  Toronto. 

Organized:    — .     Thos.  W.   Gibson,  Deputy  Minister  of  Mines; 

Willet  G.  Miller,  Provincial  Geologist. 
Publications:   Reports  of  Bureau  of  Mines,  vols.  I-XVI. 


MEXICAN  SURVEYS. 

Mexico.     Institute  Geologico  Nacional,  5a  Cipres,  Mexico  D.  F. 
Organized:  1893.     Jose  G.  Aguilera,  Director;  Juan  D.  Villarello, 

Vice-Director;   Dr.  E.  Bose,  Chief  Geologist. 
Publications:    Boletin   1-24   (4°),   1895-1906;    Parergones   (8°), 
vol.  1-2,  1903-08;  Miscellaneous  maps. 


INDEX 


PAGE 

Accuracy,  essentials  of 19 

Adaptability,  need  of,  for  field  geologist 1 

Alden,  W.  C.,  acknowledgment  to 87 

Altitudes,  estimate  of 21 

measurement  of 24 

\neroid,  care  of 14 

use  and  limitations  of 24,  25 

Angular  inclination,  conversion  of,  to  grade i 37 

Areal  geology,  purpose  of 7 

maps,  uses  of 8 

Ashley,  G.  H.,  acknowledgment  to 87 

Assistants,  selection  of 6 

work  of .  . . 20,  21 

Barometer.     See  Aneroid. 

Base  line,  measurement  of 59 

Bauxite,  schedule  for  description  of 130 

Boundaries,  formation,  representation  of 47 

Brunton  compass,  description  of <. 11 

use  of,  as  hand  level 25 

use  of,  in  determining  thickness  of  beds 30 

Brooks,  A.  H.,  acknowledgment  to 87 

Camera,  kind  of,  adapted  to  field  use 14 

use  of 51,  52 

Camp,  subsistence  in 17 

Campbell,  profile  method  devised  by 61-63 

Canadian  surveys,  personnel  of 153 

Cement  materials,  schedule  for  description  of 139 

Chemical  analyses,  information  accompanying  requests  for 81,  82 

sediments,  observations  on 99, 100 

155 


156  INDEX 

PAGE 

Circular  functions,  table  of 42 

Clastic  rocks,  observations  on 95-99 

Clay,  schedule  for  description  of 141 

Coal  samples,  collection  of 75-78 

Coal,  schedule  for  description  of 145 

Collecting  bag,  description  of 13 

Collections,  purpose  of 70 

Compass   Brunton,  advantages  of 11 

Gurley,  geologic 11 

Confidential  information,  treatment  of 5 

Cross,  Whitman,  acknowledgment  to 87 

Depth  of  beds,  methods  of  determining 32-34 

Depths  to  stratum  below  surface,  table  of 43 

Dip,  methods  of  measuring 23 

Discipline,  necessity  of,  in  camp 19 

Distance,  estimates  of 21 

methods  of  measurement 21-23 

Drift,  schedule  for  description  of 124 

Economic  geology,  purpose  of 8 

surveys,  private 4 

Educational  surveys 3 

Effusive  rocks,  observations  on 92 

Emmons,  W.  H.,  acknowledgment  to 87 

Estimates  of  distance,  altitudes,  and  angles 21 

Faults,  determination  of  dip  of 34-37 

Field  glass 14 

Field  work,  classification  of 3,  4 

preparation  for 6 

organization  for 6 

Fissure  fillings,  observations  on liO 

Formations,  field  names  for 84 

rules  for  definition  and  naming  of 83 

Fossils,  collection  of 78-81 

Gas  fields,  investigation  of 116, 117 

Gas,  schedule  for  description  of 147 

Geologic  maps,  use  of,  in  field 10 

nomenclature,  necessity  for  regulation  of 82-84 

Geological  surveys,  State,  personnel  of 149 

Geologic  work,  classification  of 7 


INDEX  157 

PAGE 

Glacial  deposits,  schedule  for  description  of 124 

geology,  methods  of 9 

Glaciers  and  glacial  deposits,  methods  of  investigation  of 105—109 

Grade,  conversion  to  angular  inclination 37 

Graton,  L.  C.,  alidade  devised  by 61 

Gravel,  schedule  for  description  of 143 

Hammers,  geologic 11-13 

Hand  levels,  Locke  and  Abney 14 

use  of 25,  26 

Igneous  rocks,  methods  of  investigation  of 90-94 

Index  maps,  preparation  of ' 48,  49 

Instruments,  list  of  geologic 11-15 

Invertebrate  fossils,  collection  of 80 

Iron  ores,  schedule  for  description  of 130 

Keith,  Arthur,  acknowledgment  to 87 

Laborers,  employment  of 6 

Land  classification  surveys,  methods  of 63-66 

Land  corners,  location  of 64—66 

Land  forms,  description  and  interpretation  of 87-89 

schedule  for  description  of 118 

Level,  wye,  use  of 26 

hand,  use  of 25,  26 

Lime  rock,  schedule  for  description  of 139 

Manganese  ore,  schedule  for  description  of 130 

Map  references,  methods  of 44,  45 

Measurement,  angular,  methods  of 23 

direct,  of  thickness  of  beds 29,  30 

horizontal,  methods  of 21-23 

vertical,  methods  of 24-26 

Mental  qualities  necessary  for  field  geologist 1 

Metalliferous  deposits,  methods  of  investigation  of 109-114 

schedule  for  description  of 126 

Metamorphic  rocks,  methods  of  investigation  of 101,  102 

Mexican  Geological  Survey,  personnel  of 154 

Minerals,  collection  of 73 

Mine  surveys,  methods  of  making 66-70 

Munn,  M.  J.,  level  notebook  devised  by 26 


158  INDEX 

PAGE 

Neatness  in  dress,  importance  of 16 

Nomenclature,  geologic,  rules  for 82—84 

Notebooks,  geologic,  description  of 15,  16 

Notes,  graphic 43-52 

map,  essentials  of 47-49 

profile  method 61-63 

traverse,  importance  of  .  .    52 

written,  essentials  of 44-47 

Observations,  field,  es3ential  qualities  of , 19,  20 

Oulcial  surveys,  appointments  in 3 

Oil  fields,  investigation  of 116,  117 

Oil,  schedule  for  description  of 117 

Opening  in  rocks,  relation  of,  to  ore  bodies 103 

Ore  specimens,  collection  of  .  .     73,  74 

Ores,  precious  and  semi-precious,  schedule  for 126 

Organic  sediments,  observations  on 99,  103 

Orientation  in  mine  surveys 67 

of  plane-table 59,  63 

Outcrop,  form  of,  on  map 37—41 

Pacing,  accuracy  of 22 

Party  chiefs,  duties  of 6 

Petrology,  schedule  for  description  of 120 

Photographs,  essentials  of,  for  geologic  use 51,  52 

Physical  qualities  necessary  for  field  geologist 1 

Placer  deposits,  investigation  of. 114—116 

schedule  for  description  of 123 

Plane-table,  geologic  and  topographic 1-1 

use  of,  in  geologic  work 57-61 

Pla.nt  fossils,  collection  of 79,  83 

Public,  relations  of  field  geologist  to 5 

Ration,  table  of  unit 11 

unit  for  stock , IS 

Reconnaissance,  preliminary,  importance  of     23 

Road  materials,  collection  of  samples  of 74,  75 

schedule  for  description  of 136 

Sampling  coals,  instructions  for 75-78 

Sand,  schedule  for  description  of 143 

Schedules,  purpose  of 86,  87 

Sedimentary  rocks,  methods  of  investigation  of 95-100 


INDEX  159 

PAOE 

Shoes,  importance  of  attention  to 17 

Sketches,  geologic,  importance  of 49,  50 

Sketching,  methods  of 50 

Smith,  Glenn  S.,  sketching  case  invented  by 55,  56 

Smith,  P.  S.,  acknowledgment  to 87 

Specimens,  labeling 70,  71 

method  of  packing 81 

rock,  collection  of 71-73 

Spencer,  A.  C.,  acknowledgment  to 87 

Stadia,  description  and  use  of 23 

State  surveys,  list  of 149-153 

Stone,  schedule  for  description  of  quarries 132 

Stratigraphic  geology,  purpose  of  .  . 7 

Structural  geology,  observations  in 103-105 

purpose  of 7 

Structure,  schedule  for  description  of 122 

Surveys,  classification  of 3 

Tape  line,  use  of 22 

Telescope  with  vertical  circle,  use  of 26 

Thickness  of  beds,  determination  by  graphic  method 29,  31,  32 

methods  of  determining  .  .  .  = 27-32 

Three-point  problem  for  plane-table  location  „ 59,  60 

Topographic  data,  preparation  of 10 

Township  plats,  use  of 65 

Training  essential  for  field  geologist 2 

Traverse,  map,  method  of  making 57 

notebook,  method  of 52-54 

sketching-case,  method  of 55-57 

Triangle  of  error,  use  of,  in  location 59 

Triangles,  solutions  of,  formulas  for 42 

United  States  Geological  Survey,  personnel  of 149 

Vertebrate  fossils,  collection  of 80,  81 

Wheel,  use  of t  in  measuring  distances 22 

Wye  level,  use  of 26 


14  DAY  USE 

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